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…for fsnotify_prepare_user_wait() Sparse reports warnings at fsnotify_prepare_user_wait() and at fsnotify_finish_user_wait() warning: context imbalance in fsnotify_finish_user_wait() - wrong count at exit warning: context imbalance in fsnotify_prepare_user_wait() - unexpected unlock The root cause is the missing annotation at fsnotify_finish_user_wait() and at fsnotify_prepare_user_wait() fsnotify_prepare_user_wait() has an extra annotation __release() that only tell Sparse and not GCC to shutdown the warning Add the missing __acquires(&fsnotify_mark_srcu) annotation Add the missing __releases(&fsnotify_mark_srcu) annotation Add the __release(&fsnotify_mark_srcu) annotation. Link: https://lore.kernel.org/r/20200413214240.15245-1-jbi.octave@gmail.com Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This patch allows to have multiple procfs instances inside the same pid namespace. The aim here is lightweight sandboxes, and to allow that we have to modernize procfs internals. 1) The main aim of this work is to have on embedded systems one supervisor for apps. Right now we have some lightweight sandbox support, however if we create pid namespacess we have to manages all the processes inside too, where our goal is to be able to run a bunch of apps each one inside its own mount namespace without being able to notice each other. We only want to use mount namespaces, and we want procfs to behave more like a real mount point. 2) Linux Security Modules have multiple ptrace paths inside some subsystems, however inside procfs, the implementation does not guarantee that the ptrace() check which triggers the security_ptrace_check() hook will always run. We have the 'hidepid' mount option that can be used to force the ptrace_may_access() check inside has_pid_permissions() to run. The problem is that 'hidepid' is per pid namespace and not attached to the mount point, any remount or modification of 'hidepid' will propagate to all other procfs mounts. This also does not allow to support Yama LSM easily in desktop and user sessions. Yama ptrace scope which restricts ptrace and some other syscalls to be allowed only on inferiors, can be updated to have a per-task context, where the context will be inherited during fork(), clone() and preserved across execve(). If we support multiple private procfs instances, then we may force the ptrace_may_access() on /proc/<pids>/ to always run inside that new procfs instances. This will allow to specifiy on user sessions if we should populate procfs with pids that the user can ptrace or not. By using Yama ptrace scope, some restricted users will only be able to see inferiors inside /proc, they won't even be able to see their other processes. Some software like Chromium, Firefox's crash handler, Wine and others are already using Yama to restrict which processes can be ptracable. With this change this will give the possibility to restrict /proc/<pids>/ but more importantly this will give desktop users a generic and usuable way to specifiy which users should see all processes and which users can not. Side notes: * This covers the lack of seccomp where it is not able to parse arguments, it is easy to install a seccomp filter on direct syscalls that operate on pids, however /proc/<pid>/ is a Linux ABI using filesystem syscalls. With this change LSMs should be able to analyze open/read/write/close... In the new patch set version I removed the 'newinstance' option as suggested by Eric W. Biederman. Selftest has been added to verify new behavior. Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
…ption If "hidepid=4" mount option is set then do not instantiate pids that we can not ptrace. "hidepid=4" means that procfs should only contain pids that the caller can ptrace. Signed-off-by: Djalal Harouni <tixxdz@gmail.com> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This allows to hide all files and directories in the procfs that are not related to tasks. Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
…s and new mount behavior Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
The hidepid parameter values are becoming more and more and it becomes difficult to remember what each new magic number means. Backward compatibility is preserved since it is possible to specify numerical value for the hidepid parameter. This does not break the fsconfig since it is not possible to specify a numerical value through it. All numeric values are converted to a string. The type FSCONFIG_SET_BINARY cannot be used to indicate a numerical value. Selftest has been added to verify this behavior. Suggested-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
To get pid_namespace from the procfs superblock should be used a special helper. This will avoid errors when s_fs_info will change the type. Link: https://lore.kernel.org/lkml/20200423200316.164518-3-gladkov.alexey@gmail.com/ Link: https://lore.kernel.org/lkml/20200423112858.95820-1-gladkov.alexey@gmail.com/ Link: https://lore.kernel.org/lkml/06B50A1C-406F-4057-BFA8-3A7729EA7469@lca.pw/ Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Alexey Gladkov <gladkov.alexey@gmail.com> writes:
Procfs modernization:
---------------------
Historically procfs was always tied to pid namespaces, during pid
namespace creation we internally create a procfs mount for it. However,
this has the effect that all new procfs mounts are just a mirror of the
internal one, any change, any mount option update, any new future
introduction will propagate to all other procfs mounts that are in the
same pid namespace.
This may have solved several use cases in that time. However today we
face new requirements, and making procfs able to support new private
instances inside same pid namespace seems a major point. If we want to
to introduce new features and security mechanisms we have to make sure
first that we do not break existing usecases. Supporting private procfs
instances will allow to support new features and behaviour without
propagating it to all other procfs mounts.
Today procfs is more of a burden especially to some Embedded, IoT,
sandbox, container use cases. In user space we are over-mounting null
or inaccessible files on top to hide files and information. If we want
to hide pids we have to create PID namespaces otherwise mount options
propagate to all other proc mounts, changing a mount option value in one
mount will propagate to all other proc mounts. If we want to introduce
new features, then they will propagate to all other mounts too, resulting
either maybe new useful functionality or maybe breaking stuff. We have
also to note that userspace should not workaround procfs, the kernel
should just provide a sane simple interface.
In this regard several developers and maintainers pointed out that
there are problems with procfs and it has to be modernized:
"Here's another one: split up and modernize /proc." by Andy Lutomirski [1]
Discussion about kernel pointer leaks:
"And yes, as Kees and Daniel mentioned, it's definitely not just dmesg.
In fact, the primary things tend to be /proc and /sys, not dmesg
itself." By Linus Torvalds [2]
Lot of other areas in the kernel and filesystems have been updated to be
able to support private instances, devpts is one major example [3].
Which will be used for:
1) Embedded systems and IoT: usually we have one supervisor for
apps, we have some lightweight sandbox support, however if we create
pid namespaces we have to manage all the processes inside too,
where our goal is to be able to run a bunch of apps each one inside
its own mount namespace, maybe use network namespaces for vlans
setups, but right now we only want mount namespaces, without all the
other complexity. We want procfs to behave more like a real file system,
and block access to inodes that belong to other users. The 'hidepid=' will
not work since it is a shared mount option.
2) Containers, sandboxes and Private instances of file systems - devpts case
Historically, lot of file systems inside Linux kernel view when instantiated
were just a mirror of an already created and mounted filesystem. This was the
case of devpts filesystem, it seems at that time the requirements were to
optimize things and reuse the same memory, etc. This design used to work but not
anymore with today's containers, IoT, hostile environments and all the privacy
challenges that Linux faces.
In that regards, devpts was updated so that each new mounts is a total
independent file system by the following patches:
"devpts: Make each mount of devpts an independent filesystem" by
Eric W. Biederman [3] [4]
3) Linux Security Modules have multiple ptrace paths inside some
subsystems, however inside procfs, the implementation does not guarantee
that the ptrace() check which triggers the security_ptrace_check() hook
will always run. We have the 'hidepid' mount option that can be used to
force the ptrace_may_access() check inside has_pid_permissions() to run.
The problem is that 'hidepid' is per pid namespace and not attached to
the mount point, any remount or modification of 'hidepid' will propagate
to all other procfs mounts.
This also does not allow to support Yama LSM easily in desktop and user
sessions. Yama ptrace scope which restricts ptrace and some other
syscalls to be allowed only on inferiors, can be updated to have a
per-task context, where the context will be inherited during fork(),
clone() and preserved across execve(). If we support multiple private
procfs instances, then we may force the ptrace_may_access() on
/proc/<pids>/ to always run inside that new procfs instances. This will
allow to specifiy on user sessions if we should populate procfs with
pids that the user can ptrace or not.
By using Yama ptrace scope, some restricted users will only be able to see
inferiors inside /proc, they won't even be able to see their other
processes. Some software like Chromium, Firefox's crash handler, Wine
and others are already using Yama to restrict which processes can be
ptracable. With this change this will give the possibility to restrict
/proc/<pids>/ but more importantly this will give desktop users a
generic and usuable way to specifiy which users should see all processes
and which user can not.
Side notes:
* This covers the lack of seccomp where it is not able to parse
arguments, it is easy to install a seccomp filter on direct syscalls
that operate on pids, however /proc/<pid>/ is a Linux ABI using
filesystem syscalls. With this change all LSMs should be able to analyze
open/read/write/close... on /proc/<pid>/
4) This will allow to implement new features either in kernel or
userspace without having to worry about procfs.
In containers, sandboxes, etc we have workarounds to hide some /proc
inodes, this should be supported natively without doing extra complex
work, the kernel should be able to support sane options that work with
today and future Linux use cases.
5) Creation of new superblock with all procfs options for each procfs
mount will fix the ignoring of mount options. The problem is that the
second mount of procfs in the same pid namespace ignores the mount
options. The mount options are ignored without error until procfs is
remounted.
Before:
proc /proc proc rw,relatime,hidepid=2 0 0
mount("proc", "/tmp/proc", "proc", 0, "hidepid=1") = 0
+++ exited with 0 +++
proc /proc proc rw,relatime,hidepid=2 0 0
proc /tmp/proc proc rw,relatime,hidepid=2 0 0
proc /proc proc rw,relatime,hidepid=1 0 0
proc /tmp/proc proc rw,relatime,hidepid=1 0 0
After:
proc /proc proc rw,relatime,hidepid=ptraceable 0 0
proc /proc proc rw,relatime,hidepid=ptraceable 0 0
proc /tmp/proc proc rw,relatime,hidepid=invisible 0 0
Introduced changes:
-------------------
Each mount of procfs creates a separate procfs instance with its own
mount options.
This series adds few new mount options:
* New 'hidepid=ptraceable' or 'hidepid=4' mount option to show only ptraceable
processes in the procfs. This allows to support lightweight sandboxes in
Embedded Linux, also solves the case for LSM where now with this mount option,
we make sure that they have a ptrace path in procfs.
* 'subset=pid' that allows to hide non-pid inodes from procfs. It can be used
in containers and sandboxes, as these are already trying to hide and block
access to procfs inodes anyway.
ChangeLog:
----------
* Rebase on top of v5.7-rc1.
* Fix a resource leak if proc is not mounted or if proc is simply reconfigured.
* Add few selftests.
* After a discussion with Eric W. Biederman, the numerical values for hidepid
parameter have been removed from uapi.
* Remove proc_self and proc_thread_self from the pid_namespace struct.
* I took into account the comment of Kees Cook.
* Update Reviewed-by tags.
* 'subset=pidfs' renamed to 'subset=pid' as suggested by Alexey Dobriyan.
* Include Reviewed-by tags.
* Rebase on top of Eric W. Biederman's procfs changes.
* Add human readable values of 'hidepid' as suggested by Andy Lutomirski.
* Started using RCU lock to clean dcache entries as suggested by Linus Torvalds.
* 'pidonly=1' renamed to 'subset=pidfs' as suggested by Alexey Dobriyan.
* HIDEPID_* moved to uapi/ as they are user interface to mount().
Suggested-by Alexey Dobriyan <adobriyan@gmail.com>
* 'hidepid=' and 'gid=' mount options are moved from pid namespace to superblock.
* 'newinstance' mount option removed as suggested by Eric W. Biederman.
Mount of procfs always creates a new instance.
* 'limit_pids' renamed to 'hidepid=3'.
* I took into account the comment of Linus Torvalds [7].
* Documentation added.
* Fixed a bug that caused a problem with the Fedora boot.
* The 'pidonly' option is visible among the mount options.
* Renamed mount options to 'newinstance' and 'pids='
Suggested-by: Andy Lutomirski <luto@kernel.org>
* Fixed order of commit, Suggested-by: Andy Lutomirski <luto@kernel.org>
* Many bug fixes.
* Removed 'unshared' mount option and replaced it with 'limit_pids'
which is attached to the current procfs mount.
Suggested-by Andy Lutomirski <luto@kernel.org>
* Do not fill dcache with pid entries that we can not ptrace.
* Many bug fixes.
References:
-----------
[1] https://lists.linuxfoundation.org/pipermail/ksummit-discuss/2017-January/004215.html
[2] http://www.openwall.com/lists/kernel-hardening/2017/10/05/5
[3] https://lwn.net/Articles/689539/
[4] http://lxr.free-electrons.com/source/Documentation/filesystems/devpts.txt?v=3.14
[5] https://lkml.org/lkml/2017/5/2/407
[6] https://lkml.org/lkml/2017/5/3/357
[7] https://lkml.org/lkml/2018/5/11/505
Alexey Gladkov (7):
proc: rename struct proc_fs_info to proc_fs_opts
proc: allow to mount many instances of proc in one pid namespace
proc: instantiate only pids that we can ptrace on 'hidepid=4' mount
option
proc: add option to mount only a pids subset
docs: proc: add documentation for "hidepid=4" and "subset=pid" options
and new mount behavior
proc: use human-readable values for hidepid
proc: use named enums for better readability
Documentation/filesystems/proc.rst | 92 +++++++++---
fs/proc/base.c | 48 +++++--
fs/proc/generic.c | 9 ++
fs/proc/inode.c | 30 +++-
fs/proc/root.c | 131 +++++++++++++-----
fs/proc/self.c | 6 +-
fs/proc/thread_self.c | 6 +-
fs/proc_namespace.c | 14 +-
include/linux/pid_namespace.h | 12 --
include/linux/proc_fs.h | 30 +++-
tools/testing/selftests/proc/.gitignore | 2 +
tools/testing/selftests/proc/Makefile | 2 +
.../selftests/proc/proc-fsconfig-hidepid.c | 50 +++++++
.../selftests/proc/proc-multiple-procfs.c | 48 +++++++
14 files changed, 384 insertions(+), 96 deletions(-)
create mode 100644 tools/testing/selftests/proc/proc-fsconfig-hidepid.c
create mode 100644 tools/testing/selftests/proc/proc-multiple-procfs.c
Link: https://lore.kernel.org/lkml/20200419141057.621356-1-gladkov.alexey@gmail.com/
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Combine the pid_task and thes test has_group_leader_pid into a single dereference by using pid_task(PIDTYPE_TGID). This makes the code simpler and proof against needing to even think about any shenanigans that de_thread might get up to. Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
There is a specific API to treat raw data as UUID, i.e. import_uuid(). Use it instead of uuid_copy() with explicit casting. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
If error code is initialized -EINVAL, there is no need to assign -EINVAL. Link: https://lore.kernel.org/r/20200426143316.29877-1-her0gyugyu@gmail.com Signed-off-by: youngjun <her0gyugyu@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Using the struct pid to refer to two tasks in de_thread was a clever idea and ultimately too clever, as it has lead to proc_flush_task being called inconsistently. To support rectifying this add hlists_swap_heads_rcu. An hlist primitive that just swaps the hlist heads of two lists. This is exactly what is needed for exchanging the pids of two tasks. Only consideration of correctness of the code has been given, as the caller is expected to be a slowpath. Link: https://lore.kernel.org/lkml/87mu6vajnq.fsf_-_@x220.int.ebiederm.org/ Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
When the thread group leader changes during exec and the old leaders thread is reaped proc_flush_pid will flush the dentries for the entire process because the leader still has it's original pid. Fix this by exchanging the pids in an rcu safe manner, and wrapping the code to do that up in a helper exchange_tids. When I removed switch_exec_pids and introduced this behavior in d73d652 ("[PATCH] pidhash: kill switch_exec_pids") there really was nothing that cared as flushing happened with the cached dentry and de_thread flushed both of them on exec. This lack of fully exchanging pids became a problem a few months later when I introduced 48e6484 ("[PATCH] proc: Rewrite the proc dentry flush on exit optimization"). Which overlooked the de_thread case was no longer swapping pids, and I was looking up proc dentries by task->pid. The current behavior isn't properly a bug as everything in proc will continue to work correctly just a little bit less efficiently. Fix this just so there are no little surprise corner cases waiting to bite people. -- Oleg points out this could be an issue in next_tgid in proc where has_group_leader_pid is called, and reording some of the assignments should fix that. -- Oleg points out this will break the 10 year old hack in __exit_signal.c > /* > * This can only happen if the caller is de_thread(). > * FIXME: this is the temporary hack, we should teach > * posix-cpu-timers to handle this case correctly. > */ > if (unlikely(has_group_leader_pid(tsk))) > posix_cpu_timers_exit_group(tsk); The code in next_tgid has been changed to use PIDTYPE_TGID, and the posix cpu timers code has been fixed so it does not need the 10 year old hack, so this should be safe to merge now. Link: https://lore.kernel.org/lkml/87h7x3ajll.fsf_-_@x220.int.ebiederm.org/ Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Fixes: 48e6484 ("[PATCH] proc: Rewrite the proc dentry flush on exit optimization"). Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
In the work to remove proc_mnt I noticed that we were calling
proc_flush_task now proc_flush_pid possibly multiple times for the same
pid because of how de_thread works.
This is a bare minimal patchset to sort out de_thread, by introducing
exchange_tids and the helper of exchange_tids hlists_swap_heads_rcu.
The actual call of exchange_tids should be slowpath so I have
prioritized readability over getting every last drop of performance.
I have also read through a bunch of the code to see if I could find
anything that would be affected by this change. Users of
has_group_leader_pid were a good canidates. But I also looked at other
cases that might have a pid->task->pid transition. I ignored other
sources of races with de_thread and exec as those are preexisting.
I found a close call with send_signals user of task_active_pid_ns, but
all pids of a thread group are guaranteeds to be in the same pid
namespace so there is not a problem.
I found a few pieces of debugging code that do:
task = pid_task(pid, PIDTYPE_PID);
if (task) {
printk("%u\n", task->pid);
}
But I can't see how we care if it happens at the wrong moment that
task->pid might not match pid_nr(pid);
Similarly because the code in posix-cpu-timers goes pid->task->pid it
feels like there should be a problem. But as the code that works with
PIDTYPE_PID is only available within the thread group, and as de_thread
kills all of the other threads before it makes any changes of this
kind the race can not happen.
In short I don't think this change will introduce any regressions.
Eric W. Biederman (2):
rculist: Add hlists_swap_heads_rcu
proc: Ensure we see the exit of each process tid exactly once
fs/exec.c | 5 +----
include/linux/pid.h | 1 +
include/linux/rculist.h | 21 +++++++++++++++++++++
kernel/pid.c | 19 +++++++++++++++++++
4 files changed, 42 insertions(+), 4 deletions(-)
Link: https://lore.kernel.org/lkml/87sggnajpv.fsf_-_@x220.int.ebiederm.org/
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Replace has_group_leader_pid with thread_group_leader. Years ago Oleg suggested changing thread_group_leader to has_group_leader_pid to handle races. Looking at the code then and now I don't see how it ever helped. Especially as then the code really did need to be the thread_group_leader. Today it doesn't make a difference if thread_group_leader races with de_thread as the task returned from lookup_task in the non-thread case is just used to find values in task->signal. Since the races with de_thread have never been handled revert has_group_header_pid to thread_group_leader for clarity. Update the comment in lookup_task to remove implementation details that are no longer true and to mention task->signal instead of task->sighand, as the relevant cpu timer details are all in task->signal. Ref: 55e8c8e ("posix-cpu-timers: Store a reference to a pid not a task") Ref: c0deae8 ("posix-cpu-timers: Rcu_read_lock/unlock protect find_task_by_vpid call") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that both !thread paths through lookup_task call thread_group_leader, unify them into the single test at the end of lookup_task. This unification just makes it clear what is happening in the gettime special case of lookup_task. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
With the introduction of exchange_tids thread_group_leader and has_group_leader_pid have become equivalent. Further at this point in the code a thread group has exactly two threads, the previous thread_group_leader that is waiting to be reaped and tsk. So we know it is impossible for tsk to be the thread_group_leader. This is also the last user of has_group_leader_pid so removing this check will allow has_group_leader_pid to be removed. So remove the "BUG_ON(has_group_leader_pid)" that will never fire. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
After the introduction of exchange_tids has_group_leader_pid is equivalent to thread_group_leader. After the last couple of cleanups has_group_leader_pid has no more callers. So remove the now unused and redundant has_group_leader_pid. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that the code stores of pid references it is no longer necessary or desirable to take a reference on task_struct in __get_task_for_clock. Instead extend the scope of rcu_read_lock and remove the reference counting on struct task_struct entirely. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Taking a clock and returning a pid_type is a more general and a superset of taking a timer and returning a pid_type. Perform this generalization so that future changes may use this code on clocks as well as timers. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that the codes store references to pids instead of referendes to tasks. Looking up a task for a clock instead of looking up a struct pid makes the code more difficult to verify it is correct than necessary. In posix_cpu_timers_create get_task_pid can race with release_task for threads and return a NULL pid. As put_pid and cpu_timer_task_rcu handle NULL pids just fine the code works without problems but it is an extra case to consider and keep in mind while verifying and modifying the code. There are races with de_thread to consider that only don't apply because thread clocks are only allowed for threads in the same thread_group. So instead of leaving a burden for people making modification to the code in the future return a rcu protected struct pid for the clock instead. The logic for __get_task_for_pid and lookup_task has been folded into the new function pid_for_clock with the only change being the logic has been modified from working on a task to working on a pid that will be returned. In posix_cpu_clock_get instead of calling pid_for_clock checking the result and then calling pid_task to get the task. The result of pid_for_clock is fed directly into pid_task. This is safe because pid_task handles NULL pids. As such an extra error check was unnecessary. Instead of hiding the flag that enables the special clock_gettime handling, I have made the 3 callers just pass the flag in themselves. That is less code and seems just as simple to work with as the wrapper functions. Historically the clock_gettime special case of allowing a process clock to be found by the thread id did not even exist [33ab0fe] but Thomas Gleixner reports that he has found code that uses that functionality [55e8c8e]. Link: https://lkml.kernel.org/r/87zhaxqkwa.fsf@nanos.tec.linutronix.de/ Ref: 33ab0fe ("posix-timers: Consolidate posix_cpu_clock_get()") Ref: 55e8c8e ("posix-cpu-timers: Store a reference to a pid not a task") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
With de_thread now calling exchange_tids has_group_leader_pid no longer
makes any sense and is equivalent to calling thread_group_leader.
As there are only 2 remaining users of has_group_leader_pid let's
update the code and get rid of has_group_leader_pid.
There is one extra patch to lookup_task that performs that unifies
to code paths that become identical when has_group_leader_pid went
away.
Eric W. Biederman (4):
posix-cpu-timer: Tidy up group_leader logic in lookup_task
posix-cpu-timer: Unify the now redundant code in lookup_task
exec: Remove BUG_ON(has_group_leader_pid)
signal: Remove has_group_leader_pid
fs/exec.c | 1 -
include/linux/sched/signal.h | 11 -----------
kernel/time/posix-cpu-timers.c | 21 ++++++++-------------
3 files changed, 8 insertions(+), 25 deletions(-)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Starting from 2c47047 ("pids: Move the pgrp and session pid pointers from task_struct to signal_struct") __task_pid_nr_ns() doesn't dereference task->group_leader, we can remove the pid_alive() check. pid_nr_ns() has to check pid != NULL anyway, pid_alive() just adds the unnecessary confusion. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
The current posix-cpu-timer code uses pids when holding persistent
references in timers. However the lookups from clock_id_t still return
tasks that need to be converted into pids for use.
This results in usage being pid->task->pid and that can race with
release_task and de_thread. This can lead to some not wrong but
surprising results. Surprising enough that Oleg and I both thought
there were some bugs in the code for a while.
This set of changes modifies the code to just lookup, verify, and return
pids from the clockid_t lookups to remove those potentialy troublesome
races.
Eric W. Biederman (3):
posix-cpu-timers: Extend rcu_read_lock removing task_struct references
posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock
kernel/time/posix-cpu-timers.c | 102 ++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 57 deletions(-)
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
In 2016 Linus moved install_exec_creds immediately after setup_new_exec, in binfmt_elf as a cleanup and as part of closing a potential information leak. Perform the same cleanup for the other binary formats. Different binary formats doing the same things the same way makes exec easier to reason about and easier to maintain. Greg Ungerer reports: > I tested the the whole series on non-MMU m68k and non-MMU arm > (exercising binfmt_flat) and it all tested out with no problems, > so for the binfmt_flat changes: Tested-by: Greg Ungerer <gerg@linux-m68k.org> Ref: 9f834ec ("binfmt_elf: switch to new creds when switching to new mm") Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
With install_exec_creds updated to follow immediately after setup_new_exec, the failure of unshare_sighand is the only code path where exec_update_mutex is held but not explicitly unlocked. Update that code path to explicitly unlock exec_update_mutex. Remove the unlocking of exec_update_mutex from free_bprm. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Update the comments and make the code easier to understand by renaming this flag. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The two functions are now always called one right after the other so merge them together to make future maintenance easier. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Let's always set special inode i_op to &ext2_special_inode_operations regardless of CONFIG_EXT2_FS_XATTR setting. It makes sence to be able to query extended inode flags (needing ->setattr and ->getattr callbacks) even when CONFIG_EXT2_FS_XATTR is not set. Link: https://lore.kernel.org/r/20200522044035.24190-1-cgxu519@mykernel.net Signed-off-by: Chengguang Xu <cgxu519@mykernel.net> Signed-off-by: Jan Kara <jack@suse.cz>
Define ext2_listxattr to NULL when CONFIG_EROFS_FS_XATTR is not enabled, then we can remove many ugly ifdef macros in the code. Link: https://lore.kernel.org/r/20200522044035.24190-2-cgxu519@mykernel.net Signed-off-by: Chengguang Xu <cgxu519@mykernel.net> Signed-off-by: Jan Kara <jack@suse.cz>
The comments in fanotify_group_event_mask() say: "If the event is on dir/child and this mark doesn't care about events on dir/child, don't send it!" Specifically, mount and filesystem marks do not care about events on child, but they can still specify an ignore mask for those events. For example, a group that has: - A mount mark with mask 0 and ignore_mask FAN_OPEN - An inode mark on a directory with mask FAN_OPEN | FAN_OPEN_EXEC with flag FAN_EVENT_ON_CHILD A child file open for exec would be reported to group with the FAN_OPEN event despite the fact that FAN_OPEN is in ignore mask of mount mark, because the mark iteration loop skips over non-inode marks for events on child when calculating the ignore mask. Move ignore mask calculation to the top of the iteration loop block before excluding marks for events on dir/child. Link: https://lore.kernel.org/r/20200524072441.18258-1-amir73il@gmail.com Reported-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/linux-fsdevel/20200521162443.GA26052@quack2.suse.cz/ Fixes: 55bf882 "fanotify: fix merging marks masks with FAN_ONDIR" Fixes: b469e7e "fanotify: fix handling of events on child..." Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
The change to bprm->have_execfd was incomplete, leading to a build failure: fs/binfmt_elf_fdpic.c: In function 'create_elf_fdpic_tables': fs/binfmt_elf_fdpic.c:591:27: error: 'BINPRM_FLAGS_EXECFD' undeclared Change the last user of BINPRM_FLAGS_EXECFD in a corresponding way. Reported-by: Valdis Klētnieks <valdis.kletnieks@vt.edu> Fixes: b8a61c9 ("exec: Generic execfd support") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
…reds") This is a bug fix and one of two places where I have found that the result of calling security_bprm_repopulate_creds more than once on different bprm->files depends on all of the bprm->files not just the file bprm->file. I intend to fix both of those cases and then modify the code to only call security_bprm_repopulate_creds on the final bprm file. So merge this change in so I hopefully reduce conflicts for others and I make it possible to build on top of this change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Use kcalloc instead of kmalloc in the comment according to the previous kcalloc() call. Link: https://lore.kernel.org/r/1590714150-15895-1-git-send-email-wang.yi59@zte.com.cn Signed-off-by: Liao Pingfang <liao.pingfang@zte.com.cn> Signed-off-by: Jan Kara <jack@suse.cz>
There is a small bug in the code that recomputes parts of bprm->cred for every bprm->file. The code never recomputes the part of clear_dangerous_personality_flags it is responsible for. Which means that in practice if someone creates a sgid script the interpreter will not be able to use any of: READ_IMPLIES_EXEC ADDR_NO_RANDOMIZE ADDR_COMPAT_LAYOUT MMAP_PAGE_ZERO. This accentially clearing of personality flags probably does not matter in practice because no one has complained but it does make the code more difficult to understand. Further remaining bug compatible prevents the recomputation from being removed and replaced by simply computing bprm->cred once from the final bprm->file. Making this change removes the last behavior difference between computing bprm->creds from the final file and recomputing bprm->cred several times. Which allows this behavior change to be justified for it's own reasons, and for any but hunts looking into why the behavior changed to wind up here instead of in the code that will follow that computes bprm->cred from the final bprm->file. This small logic bug appears to have existed since the code started clearing dangerous personality bits. History Tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Fixes: 1bb0fa1 ("[PATCH] NX: clean up legacy binary support") Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Move the computation of creds from prepare_binfmt into begin_new_exec so that the creds need only be computed once. This is just code reorganization no semantic changes of any kind are made. Moving the computation is safe. I have looked through the kernel and verified none of the binfmts look at bprm->cred directly, and that there are no helpers that look at bprm->cred indirectly. Which means that it is not a problem to compute the bprm->cred later in the execution flow as it is not used until it becomes current->cred. A new function bprm_creds_from_file is added to contain the work that needs to be done. bprm_creds_from_file first computes which file bprm->executable or most likely bprm->file that the bprm->creds will be computed from. The funciton bprm_fill_uid is updated to receive the file instead of accessing bprm->file. The now unnecessary work needed to reset the bprm->cred->euid, and bprm->cred->egid is removed from brpm_fill_uid. A small comment to document that bprm_fill_uid now only deals with the work to handle suid and sgid files. The default case is already heandled by prepare_exec_creds. The function security_bprm_repopulate_creds is renamed security_bprm_creds_from_file and now is explicitly passed the file from which to compute the creds. The documentation of the bprm_creds_from_file security hook is updated to explain when the hook is called and what it needs to do. The file is passed from cap_bprm_creds_from_file into get_file_caps so that the caps are computed for the appropriate file. The now unnecessary work in cap_bprm_creds_from_file to reset the ambient capabilites has been removed. A small comment to document that the work of cap_bprm_creds_from_file is to read capabilities from the files secureity attribute and derive capabilities from the fact the user had uid 0 has been added. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Recomputing the uids, gids, capabilities, and related flags each time a
new bprm->file is set is error prone and unnecessary.
This set of changes splits per_clear temporarily into two separate
variables. This is the last change necessary to ensure that
everything that is computed from brpm->file in bprm->cred is
recomputed every time a new bprm->file is set. Then the code is
refactored to compute bprm->cred from bprm->file when the final
brpm->file is known, removing the need for recomputation entirely.
Doing this in two steps should allow anyone who has problems later to
bisect and tell if it was the semantic change or the refactoring that
caused them problems.
Eric W. Biederman (2):
exec: Add a per bprm->file version of per_clear
exec: Compute file based creds only once
fs/binfmt_misc.c | 2 +-
fs/exec.c | 57 ++++++++++++++++++-------------------------
include/linux/binfmts.h | 9 ++-----
include/linux/lsm_hook_defs.h | 2 +-
include/linux/lsm_hooks.h | 22 +++++++++--------
include/linux/security.h | 9 ++++---
security/commoncap.c | 22 +++++++++--------
security/security.c | 4 +--
8 files changed, 59 insertions(+), 68 deletions(-)
Merge branch 'exec-norecompute-v2' into exec-next
…el/git/dlemoal/zonefs Pull zonefs update from Damien Le Moal: "Only one patch in this pull request to cleanup handling of uuid using the import_uuid() helper, from Andy" * tag 'zonefs-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs: zonefs: Replace uuid_copy() with import_uuid()
…ux/kernel/git/jack/linux-fs Pull fsnotify updates from Jan Kara: "Several smaller fixes and cleanups for fsnotify subsystem" * tag 'fsnotify_for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fanotify: fix ignore mask logic for events on child and on dir fanotify: don't write with size under sizeof(response) fsnotify: Remove proc_fs.h include fanotify: remove reference to fill_event_metadata() fsnotify: add mutex destroy fanotify: prefix should_merge() fanotify: Replace zero-length array with flexible-array inotify: Fix error return code assignment flow. fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()
…/git/jack/linux-fs Pull ext2 and reiserfs cleanups from Jan Kara: "Two small cleanups for ext2 and one for reiserfs" * tag 'for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: reiserfs: Replace kmalloc with kcalloc in the comment ext2: code cleanup by removing ifdef macro surrounding ext2: Fix i_op setting for special inode
…l/git/ebiederm/user-namespace Pull proc updates from Eric Biederman: "This has four sets of changes: - modernize proc to support multiple private instances - ensure we see the exit of each process tid exactly - remove has_group_leader_pid - use pids not tasks in posix-cpu-timers lookup Alexey updated proc so each mount of proc uses a new superblock. This allows people to actually use mount options with proc with no fear of messing up another mount of proc. Given the kernel's internal mounts of proc for things like uml this was a real problem, and resulted in Android's hidepid mount options being ignored and introducing security issues. The rest of the changes are small cleanups and fixes that came out of my work to allow this change to proc. In essence it is swapping the pids in de_thread during exec which removes a special case the code had to handle. Then updating the code to stop handling that special case" * 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc: proc_pid_ns takes super_block as an argument remove the no longer needed pid_alive() check in __task_pid_nr_ns() posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type posix-cpu-timers: Extend rcu_read_lock removing task_struct references signal: Remove has_group_leader_pid exec: Remove BUG_ON(has_group_leader_pid) posix-cpu-timer: Unify the now redundant code in lookup_task posix-cpu-timer: Tidy up group_leader logic in lookup_task proc: Ensure we see the exit of each process tid exactly once rculist: Add hlists_swap_heads_rcu proc: Use PIDTYPE_TGID in next_tgid Use proc_pid_ns() to get pid_namespace from the proc superblock proc: use named enums for better readability proc: use human-readable values for hidepid docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior proc: add option to mount only a pids subset proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option proc: allow to mount many instances of proc in one pid namespace proc: rename struct proc_fs_info to proc_fs_opts
…l/git/ebiederm/user-namespace Pull execve updates from Eric Biederman: "Last cycle for the Nth time I ran into bugs and quality of implementation issues related to exec that could not be easily be fixed because of the way exec is implemented. So I have been digging into exec and cleanup up what I can. I don't think I have exec sorted out enough to fix the issues I started with but I have made some headway this cycle with 4 sets of changes. - promised cleanups after introducing exec_update_mutex - trivial cleanups for exec - control flow simplifications - remove the recomputation of bprm->cred The net result is code that is a bit easier to understand and work with and a decrease in the number of lines of code (if you don't count the added tests)" * 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits) exec: Compute file based creds only once exec: Add a per bprm->file version of per_clear binfmt_elf_fdpic: fix execfd build regression selftests/exec: Add binfmt_script regression test exec: Remove recursion from search_binary_handler exec: Generic execfd support exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC exec: Move the call of prepare_binprm into search_binary_handler exec: Allow load_misc_binary to call prepare_binprm unconditionally exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds exec: Teach prepare_exec_creds how exec treats uids & gids exec: Set the point of no return sooner exec: Move handling of the point of no return to the top level exec: Run sync_mm_rss before taking exec_update_mutex exec: Fix spelling of search_binary_handler in a comment exec: Move the comment from above de_thread to above unshare_sighand exec: Rename flush_old_exec begin_new_exec exec: Move most of setup_new_exec into flush_old_exec exec: In setup_new_exec cache current in the local variable me ...
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In xfs_growfs_rt(), we enlarge bitmap and summary files by allocating
new blocks for both files. For each of the new blocks allocated, we
allocate an xfs_buf, zero the payload, log the contents and commit the
transaction. Hence these buffers will eventually find themselves
appended to list at xfs_ail->ail_buf_list.
Later, xfs_growfs_rt() loops across all of the new blocks belonging to
the bitmap inode to set the bitmap values to 1. In doing so, it
allocates a new transaction and invokes the following sequence of
functions,
- xfs_rtfree_range()
- xfs_rtmodify_range()
- xfs_rtbuf_get()
We pass '&xfs_rtbuf_ops' as the ops pointer to xfs_trans_read_buf().
- xfs_trans_read_buf()
We find the xfs_buf of interest in per-ag hash table, invoke
xfs_buf_reverify() which ends up assigning '&xfs_rtbuf_ops' to
xfs_buf->b_ops.
On the other hand, if xfs_growfs_rt_alloc() had allocated a few blocks
for the bitmap inode and returned with an error, all the xfs_bufs
corresponding to the new bitmap blocks that have been allocated would
continue to be on xfs_ail->ail_buf_list list without ever having a
non-NULL value assigned to their b_ops members. An AIL flush operation
would then trigger the following warning message to be printed on the
console,
XFS (loop0): _xfs_buf_ioapply: no buf ops on daddr 0x58 len 8
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
CPU: 3 PID: 449 Comm: xfsaild/loop0 Not tainted 5.8.0-rc4-chandan-00038-g4d8c2b9de9ab-dirty #37
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
dump_stack+0x57/0x70
_xfs_buf_ioapply+0x37c/0x3b0
? xfs_rw_bdev+0x1e0/0x1e0
? xfs_buf_delwri_submit_buffers+0xd4/0x210
__xfs_buf_submit+0x6d/0x1f0
xfs_buf_delwri_submit_buffers+0xd4/0x210
xfsaild+0x2c8/0x9e0
? __switch_to_asm+0x42/0x70
? xfs_trans_ail_cursor_first+0x80/0x80
kthread+0xfe/0x140
? kthread_park+0x90/0x90
ret_from_fork+0x22/0x30
This message indicates that the xfs_buf had its b_ops member set to
NULL.
This commit fixes the issue by assigning "&xfs_rtbuf_ops" to b_ops
member of each of the xfs_bufs logged by xfs_growfs_rt_alloc().
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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In a memory pressure situation, I'm seeing the lockdep WARNING below. Actually, this is similar to a known false positive which is already addressed by commit 6dcde60 ("xfs: more lockdep whackamole with kmem_alloc*"). This warning still persists because it's not from kmalloc() itself but from an allocation for kmemleak object. While kmalloc() itself suppress the warning with __GFP_NOLOCKDEP, gfp_kmemleak_mask() is dropping the flag for the kmemleak's allocation. Allow __GFP_NOLOCKDEP to be passed to kmemleak's allocation, so that the warning for it is also suppressed. ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc7-BTRFS-ZNS+ #37 Not tainted ------------------------------------------------------ kswapd0/288 is trying to acquire lock: ffff88825ab45df0 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0x8a/0x250 but task is already holding lock: ffffffff848cc1e0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x112/0x160 kmem_cache_alloc+0x48/0x400 create_object.isra.0+0x42/0xb10 kmemleak_alloc+0x48/0x80 __kmalloc+0x228/0x440 kmem_alloc+0xd3/0x2b0 kmem_alloc_large+0x5a/0x1c0 xfs_attr_copy_value+0x112/0x190 xfs_attr_shortform_getvalue+0x1fc/0x300 xfs_attr_get_ilocked+0x125/0x170 xfs_attr_get+0x329/0x450 xfs_get_acl+0x18d/0x430 get_acl.part.0+0xb6/0x1e0 posix_acl_xattr_get+0x13a/0x230 vfs_getxattr+0x21d/0x270 getxattr+0x126/0x310 __x64_sys_fgetxattr+0x1a6/0x2a0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (&xfs_nondir_ilock_class){++++}-{3:3}: __lock_acquire+0x2c0f/0x5a00 lock_acquire+0x1a1/0x4b0 down_read_nested+0x50/0x90 xfs_ilock+0x8a/0x250 xfs_can_free_eofblocks+0x34f/0x570 xfs_inactive+0x411/0x520 xfs_fs_destroy_inode+0x2c8/0x710 destroy_inode+0xc5/0x1a0 evict+0x444/0x620 dispose_list+0xfe/0x1c0 prune_icache_sb+0xdc/0x160 super_cache_scan+0x31e/0x510 do_shrink_slab+0x337/0x8e0 shrink_slab+0x362/0x5c0 shrink_node+0x7a7/0x1a40 balance_pgdat+0x64e/0xfe0 kswapd+0x590/0xa80 kthread+0x38c/0x460 ret_from_fork+0x22/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&xfs_nondir_ilock_class); lock(fs_reclaim); lock(&xfs_nondir_ilock_class); *** DEADLOCK *** 3 locks held by kswapd0/288: #0: ffffffff848cc1e0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff848a08d8 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x269/0x5c0 #2: ffff8881a7a820e8 (&type->s_umount_key#60){++++}-{3:3}, at: super_cache_scan+0x5a/0x510 Link: https://lkml.kernel.org/r/20210907055659.3182992-1-naohiro.aota@wdc.com Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: "Darrick J . Wong" <djwong@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We received a report[1] of kernel crashes when Cilium is used in XDP
mode with virtio_net after updating to newer kernels. After
investigating the reason it turned out that when using mergeable bufs
with an XDP program which adjusts xdp.data or xdp.data_meta page_to_buf()
calculates the build_skb address wrong because the offset can become less
than the headroom so it gets the address of the previous page (-X bytes
depending on how lower offset is):
page_to_skb: page addr ffff9eb2923e2000 buf ffff9eb2923e1ffc offset 252 headroom 256
This is a pr_err() I added in the beginning of page_to_skb which clearly
shows offset that is less than headroom by adding 4 bytes of metadata
via an xdp prog. The calculations done are:
receive_mergeable():
headroom = VIRTIO_XDP_HEADROOM; // VIRTIO_XDP_HEADROOM == 256 bytes
offset = xdp.data - page_address(xdp_page) -
vi->hdr_len - metasize;
page_to_skb():
p = page_address(page) + offset;
...
buf = p - headroom;
Now buf goes -4 bytes from the page's starting address as can be seen
above which is set as skb->head and skb->data by build_skb later. Depending
on what's done with the skb (when it's freed most often) we get all kinds
of corruptions and BUG_ON() triggers in mm[2]. We have to recalculate
the new headroom after the xdp program has run, similar to how offset
and len are recalculated. Headroom is directly related to
data_hard_start, data and data_meta, so we use them to get the new size.
The result is correct (similar pr_err() in page_to_skb, one case of
xdp_page and one case of virtnet buf):
a) Case with 4 bytes of metadata
[ 115.949641] page_to_skb: page addr ffff8b4dcfad2000 offset 252 headroom 252
[ 121.084105] page_to_skb: page addr ffff8b4dcf018000 offset 20732 headroom 252
b) Case of pushing data +32 bytes
[ 153.181401] page_to_skb: page addr ffff8b4dd0c4d000 offset 288 headroom 288
[ 158.480421] page_to_skb: page addr ffff8b4dd00b0000 offset 24864 headroom 288
c) Case of pushing data -33 bytes
[ 835.906830] page_to_skb: page addr ffff8b4dd3270000 offset 223 headroom 223
[ 840.839910] page_to_skb: page addr ffff8b4dcdd68000 offset 12511 headroom 223
Offset and headroom are equal because offset points to the start of
reserved bytes for the virtio_net header which are at buf start +
headroom, while data points at buf start + vnet hdr size + headroom so
when data or data_meta are adjusted by the xdp prog both the headroom size
and the offset change equally. We can use data_hard_start to compute the
new headroom after the xdp prog (linearized / page start case, the
virtnet buf case is similar just with bigger base offset):
xdp.data_hard_start = page_address + vnet_hdr
xdp.data = page_address + vnet_hdr + headroom
new headroom after xdp prog = xdp.data - xdp.data_hard_start - metasize
An example reproducer xdp prog[3] is below.
[1] cilium/cilium#19453
[2] Two of the many traces:
[ 40.437400] BUG: Bad page state in process swapper/0 pfn:14940
[ 40.916726] BUG: Bad page state in process systemd-resolve pfn:053b7
[ 41.300891] kernel BUG at include/linux/mm.h:720!
[ 41.301801] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 41.302784] CPU: 1 PID: 1181 Comm: kubelet Kdump: loaded Tainted: G B W 5.18.0-rc1+ #37
[ 41.304458] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014
[ 41.306018] RIP: 0010:page_frag_free+0x79/0xe0
[ 41.306836] Code: 00 00 75 ea 48 8b 07 a9 00 00 01 00 74 e0 48 8b 47 48 48 8d 50 ff a8 01 48 0f 45 fa eb d0 48 c7 c6 18 b8 30 a6 e8 d7 f8 fc ff <0f> 0b 48 8d 78 ff eb bc 48 8b 07 a9 00 00 01 00 74 3a 66 90 0f b6
[ 41.310235] RSP: 0018:ffffac05c2a6bc78 EFLAGS: 00010292
[ 41.311201] RAX: 000000000000003e RBX: 0000000000000000 RCX: 0000000000000000
[ 41.312502] RDX: 0000000000000001 RSI: ffffffffa6423004 RDI: 00000000ffffffff
[ 41.313794] RBP: ffff993c98823600 R08: 0000000000000000 R09: 00000000ffffdfff
[ 41.315089] R10: ffffac05c2a6ba68 R11: ffffffffa698ca28 R12: ffff993c98823600
[ 41.316398] R13: ffff993c86311ebc R14: 0000000000000000 R15: 000000000000005c
[ 41.317700] FS: 00007fe13fc56740(0000) GS:ffff993cdd900000(0000) knlGS:0000000000000000
[ 41.319150] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 41.320152] CR2: 000000c00008a000 CR3: 0000000014908000 CR4: 0000000000350ee0
[ 41.321387] Call Trace:
[ 41.321819] <TASK>
[ 41.322193] skb_release_data+0x13f/0x1c0
[ 41.322902] __kfree_skb+0x20/0x30
[ 41.343870] tcp_recvmsg_locked+0x671/0x880
[ 41.363764] tcp_recvmsg+0x5e/0x1c0
[ 41.384102] inet_recvmsg+0x42/0x100
[ 41.406783] ? sock_recvmsg+0x1d/0x70
[ 41.428201] sock_read_iter+0x84/0xd0
[ 41.445592] ? 0xffffffffa3000000
[ 41.462442] new_sync_read+0x148/0x160
[ 41.479314] ? 0xffffffffa3000000
[ 41.496937] vfs_read+0x138/0x190
[ 41.517198] ksys_read+0x87/0xc0
[ 41.535336] do_syscall_64+0x3b/0x90
[ 41.551637] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 41.568050] RIP: 0033:0x48765b
[ 41.583955] Code: e8 4a 35 fe ff eb 88 cc cc cc cc cc cc cc cc e8 fb 7a fe ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30
[ 41.632818] RSP: 002b:000000c000a2f5b8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
[ 41.664588] RAX: ffffffffffffffda RBX: 000000c000062000 RCX: 000000000048765b
[ 41.681205] RDX: 0000000000005e54 RSI: 000000c000e66000 RDI: 0000000000000016
[ 41.697164] RBP: 000000c000a2f608 R08: 0000000000000001 R09: 00000000000001b4
[ 41.713034] R10: 00000000000000b6 R11: 0000000000000212 R12: 00000000000000e9
[ 41.728755] R13: 0000000000000001 R14: 000000c000a92000 R15: ffffffffffffffff
[ 41.744254] </TASK>
[ 41.758585] Modules linked in: br_netfilter bridge veth netconsole virtio_net
and
[ 33.524802] BUG: Bad page state in process systemd-network pfn:11e60
[ 33.528617] page ffffe05dc0147b00 ffffe05dc04e7a00 ffff8ae9851ec000 (1) len 82 offset 252 metasize 4 hroom 0 hdr_len 12 data ffff8ae9851ec10c data_meta ffff8ae9851ec108 data_end ffff8ae9851ec14e
[ 33.529764] page:000000003792b5ba refcount:0 mapcount:-512 mapping:0000000000000000 index:0x0 pfn:0x11e60
[ 33.532463] flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)
[ 33.532468] raw: 000fffffc0000000 0000000000000000 dead000000000122 0000000000000000
[ 33.532470] raw: 0000000000000000 0000000000000000 00000000fffffdff 0000000000000000
[ 33.532471] page dumped because: nonzero mapcount
[ 33.532472] Modules linked in: br_netfilter bridge veth netconsole virtio_net
[ 33.532479] CPU: 0 PID: 791 Comm: systemd-network Kdump: loaded Not tainted 5.18.0-rc1+ #37
[ 33.532482] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014
[ 33.532484] Call Trace:
[ 33.532496] <TASK>
[ 33.532500] dump_stack_lvl+0x45/0x5a
[ 33.532506] bad_page.cold+0x63/0x94
[ 33.532510] free_pcp_prepare+0x290/0x420
[ 33.532515] free_unref_page+0x1b/0x100
[ 33.532518] skb_release_data+0x13f/0x1c0
[ 33.532524] kfree_skb_reason+0x3e/0xc0
[ 33.532527] ip6_mc_input+0x23c/0x2b0
[ 33.532531] ip6_sublist_rcv_finish+0x83/0x90
[ 33.532534] ip6_sublist_rcv+0x22b/0x2b0
[3] XDP program to reproduce(xdp_pass.c):
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
SEC("xdp_pass")
int xdp_pkt_pass(struct xdp_md *ctx)
{
bpf_xdp_adjust_head(ctx, -(int)32);
return XDP_PASS;
}
char _license[] SEC("license") = "GPL";
compile: clang -O2 -g -Wall -target bpf -c xdp_pass.c -o xdp_pass.o
load on virtio_net: ip link set enp1s0 xdpdrv obj xdp_pass.o sec xdp_pass
CC: stable@vger.kernel.org
CC: Jason Wang <jasowang@redhat.com>
CC: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
CC: Daniel Borkmann <daniel@iogearbox.net>
CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: virtualization@lists.linux-foundation.org
Fixes: 8fb7da9 ("virtio_net: get build_skb() buf by data ptr")
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20220425103703.3067292-1-razor@blackwall.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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This change fixes the following kernel NULL pointer dereference which is reproduced by blktests srp/007 occasionally. BUG: kernel NULL pointer dereference, address: 0000000000000170 PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 9 Comm: kworker/0:1H Kdump: loaded Not tainted 6.0.0-rc1+ #37 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-29-g6a62e0cb0dfe-prebuilt.qemu.org 04/01/2014 Workqueue: 0x0 (kblockd) RIP: 0010:srp_recv_done+0x176/0x500 [ib_srp] Code: 00 4d 85 ff 0f 84 52 02 00 00 48 c7 82 80 02 00 00 00 00 00 00 4c 89 df 4c 89 14 24 e8 53 d3 4a f6 4c 8b 14 24 41 0f b6 42 13 <41> 89 87 70 01 00 00 41 0f b6 52 12 f6 c2 02 74 44 41 8b 42 1c b9 RSP: 0018:ffffaef7c0003e28 EFLAGS: 00000282 RAX: 0000000000000000 RBX: ffff9bc9486dea60 RCX: 0000000000000000 RDX: 0000000000000102 RSI: ffffffffb76bbd0e RDI: 00000000ffffffff RBP: ffff9bc980099a00 R08: 0000000000000001 R09: 0000000000000001 R10: ffff9bca53ef0000 R11: ffff9bc980099a10 R12: ffff9bc956e14000 R13: ffff9bc9836b9cb0 R14: ffff9bc9557b4480 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff9bc97ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000170 CR3: 0000000007e04000 CR4: 00000000000006f0 Call Trace: <IRQ> __ib_process_cq+0xb7/0x280 [ib_core] ib_poll_handler+0x2b/0x130 [ib_core] irq_poll_softirq+0x93/0x150 __do_softirq+0xee/0x4b8 irq_exit_rcu+0xf7/0x130 sysvec_apic_timer_interrupt+0x8e/0xc0 </IRQ> Fixes: ad215aa ("RDMA/srp: Make struct scsi_cmnd and struct srp_request adjacent") Link: https://lore.kernel.org/r/20220831081626.18712-1-yangx.jy@fujitsu.com Signed-off-by: Xiao Yang <yangx.jy@fujitsu.com> Acked-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Leon Romanovsky <leon@kernel.org>
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indx_read is called when we have some NTFS directory operations that need more information from the index buffers. This adds a sanity check to make sure the returned index buffer length is legit, or we may have some out-of-bound memory accesses. [ 560.897595] BUG: KASAN: slab-out-of-bounds in hdr_find_e.isra.0+0x10c/0x320 [ 560.898321] Read of size 2 at addr ffff888009497238 by task exp/245 [ 560.898760] [ 560.899129] CPU: 0 PID: 245 Comm: exp Not tainted 6.0.0-rc6 #37 [ 560.899505] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 560.900170] Call Trace: [ 560.900407] <TASK> [ 560.900732] dump_stack_lvl+0x49/0x63 [ 560.901108] print_report.cold+0xf5/0x689 [ 560.901395] ? hdr_find_e.isra.0+0x10c/0x320 [ 560.901716] kasan_report+0xa7/0x130 [ 560.901950] ? hdr_find_e.isra.0+0x10c/0x320 [ 560.902208] __asan_load2+0x68/0x90 [ 560.902427] hdr_find_e.isra.0+0x10c/0x320 [ 560.902846] ? cmp_uints+0xe0/0xe0 [ 560.903363] ? cmp_sdh+0x90/0x90 [ 560.903883] ? ntfs_bread_run+0x190/0x190 [ 560.904196] ? rwsem_down_read_slowpath+0x750/0x750 [ 560.904969] ? ntfs_fix_post_read+0xe0/0x130 [ 560.905259] ? __kasan_check_write+0x14/0x20 [ 560.905599] ? up_read+0x1a/0x90 [ 560.905853] ? indx_read+0x22c/0x380 [ 560.906096] indx_find+0x2ef/0x470 [ 560.906352] ? indx_find_buffer+0x2d0/0x2d0 [ 560.906692] ? __kasan_kmalloc+0x88/0xb0 [ 560.906977] dir_search_u+0x196/0x2f0 [ 560.907220] ? ntfs_nls_to_utf16+0x450/0x450 [ 560.907464] ? __kasan_check_write+0x14/0x20 [ 560.907747] ? mutex_lock+0x8f/0xe0 [ 560.907970] ? __mutex_lock_slowpath+0x20/0x20 [ 560.908214] ? kmem_cache_alloc+0x143/0x4b0 [ 560.908459] ntfs_lookup+0xe0/0x100 [ 560.908788] __lookup_slow+0x116/0x220 [ 560.909050] ? lookup_fast+0x1b0/0x1b0 [ 560.909309] ? lookup_fast+0x13f/0x1b0 [ 560.909601] walk_component+0x187/0x230 [ 560.909944] link_path_walk.part.0+0x3f0/0x660 [ 560.910285] ? handle_lookup_down+0x90/0x90 [ 560.910618] ? path_init+0x642/0x6e0 [ 560.911084] ? percpu_counter_add_batch+0x6e/0xf0 [ 560.912559] ? __alloc_file+0x114/0x170 [ 560.913008] path_openat+0x19c/0x1d10 [ 560.913419] ? getname_flags+0x73/0x2b0 [ 560.913815] ? kasan_save_stack+0x3a/0x50 [ 560.914125] ? kasan_save_stack+0x26/0x50 [ 560.914542] ? __kasan_slab_alloc+0x6d/0x90 [ 560.914924] ? kmem_cache_alloc+0x143/0x4b0 [ 560.915339] ? getname_flags+0x73/0x2b0 [ 560.915647] ? getname+0x12/0x20 [ 560.916114] ? __x64_sys_open+0x4c/0x60 [ 560.916460] ? path_lookupat.isra.0+0x230/0x230 [ 560.916867] ? __isolate_free_page+0x2e0/0x2e0 [ 560.917194] do_filp_open+0x15c/0x1f0 [ 560.917448] ? may_open_dev+0x60/0x60 [ 560.917696] ? expand_files+0xa4/0x3a0 [ 560.917923] ? __kasan_check_write+0x14/0x20 [ 560.918185] ? _raw_spin_lock+0x88/0xdb [ 560.918409] ? _raw_spin_lock_irqsave+0x100/0x100 [ 560.918783] ? _find_next_bit+0x4a/0x130 [ 560.919026] ? _raw_spin_unlock+0x19/0x40 [ 560.919276] ? alloc_fd+0x14b/0x2d0 [ 560.919635] do_sys_openat2+0x32a/0x4b0 [ 560.920035] ? file_open_root+0x230/0x230 [ 560.920336] ? __rcu_read_unlock+0x5b/0x280 [ 560.920813] do_sys_open+0x99/0xf0 [ 560.921208] ? filp_open+0x60/0x60 [ 560.921482] ? exit_to_user_mode_prepare+0x49/0x180 [ 560.921867] __x64_sys_open+0x4c/0x60 [ 560.922128] do_syscall_64+0x3b/0x90 [ 560.922369] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 560.923030] RIP: 0033:0x7f7dff2e4469 [ 560.923681] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 088 [ 560.924451] RSP: 002b:00007ffd41a210b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000002 [ 560.925168] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7dff2e4469 [ 560.925655] RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007ffd41a211f0 [ 560.926085] RBP: 00007ffd41a252a0 R08: 00007f7dff60fba0 R09: 00007ffd41a25388 [ 560.926405] R10: 0000000000400b80 R11: 0000000000000206 R12: 00000000004004e0 [ 560.926867] R13: 00007ffd41a25380 R14: 0000000000000000 R15: 0000000000000000 [ 560.927241] </TASK> [ 560.927491] [ 560.927755] Allocated by task 245: [ 560.928409] kasan_save_stack+0x26/0x50 [ 560.929271] __kasan_kmalloc+0x88/0xb0 [ 560.929778] __kmalloc+0x192/0x320 [ 560.930023] indx_read+0x249/0x380 [ 560.930224] indx_find+0x2a2/0x470 [ 560.930695] dir_search_u+0x196/0x2f0 [ 560.930892] ntfs_lookup+0xe0/0x100 [ 560.931115] __lookup_slow+0x116/0x220 [ 560.931323] walk_component+0x187/0x230 [ 560.931570] link_path_walk.part.0+0x3f0/0x660 [ 560.931791] path_openat+0x19c/0x1d10 [ 560.932008] do_filp_open+0x15c/0x1f0 [ 560.932226] do_sys_openat2+0x32a/0x4b0 [ 560.932413] do_sys_open+0x99/0xf0 [ 560.932709] __x64_sys_open+0x4c/0x60 [ 560.933417] do_syscall_64+0x3b/0x90 [ 560.933776] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 560.934235] [ 560.934486] The buggy address belongs to the object at ffff888009497000 [ 560.934486] which belongs to the cache kmalloc-512 of size 512 [ 560.935239] The buggy address is located 56 bytes to the right of [ 560.935239] 512-byte region [ffff888009497000, ffff888009497200) [ 560.936153] [ 560.937326] The buggy address belongs to the physical page: [ 560.938228] page:0000000062a3dfae refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9496 [ 560.939616] head:0000000062a3dfae order:1 compound_mapcount:0 compound_pincount:0 [ 560.940219] flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) [ 560.942702] raw: 000fffffc0010200 ffffea0000164f80 dead000000000005 ffff888001041c80 [ 560.943932] raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 [ 560.944568] page dumped because: kasan: bad access detected [ 560.945735] [ 560.946112] Memory state around the buggy address: [ 560.946870] ffff888009497100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 560.947242] ffff888009497180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 560.947611] >ffff888009497200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 560.947915] ^ [ 560.948249] ffff888009497280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 560.948687] ffff888009497300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc Signed-off-by: Edward Lo <edward.lo@ambergroup.io> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
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Though we already have some sanity checks while enumerating attributes, resident attribute names aren't included. This patch checks the resident attribute names are in the valid ranges. [ 259.209031] BUG: KASAN: slab-out-of-bounds in ni_create_attr_list+0x1e1/0x850 [ 259.210770] Write of size 426 at addr ffff88800632f2b2 by task exp/255 [ 259.211551] [ 259.212035] CPU: 0 PID: 255 Comm: exp Not tainted 6.0.0-rc6 #37 [ 259.212955] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 259.214387] Call Trace: [ 259.214640] <TASK> [ 259.214895] dump_stack_lvl+0x49/0x63 [ 259.215284] print_report.cold+0xf5/0x689 [ 259.215565] ? kasan_poison+0x3c/0x50 [ 259.215778] ? kasan_unpoison+0x28/0x60 [ 259.215991] ? ni_create_attr_list+0x1e1/0x850 [ 259.216270] kasan_report+0xa7/0x130 [ 259.216481] ? ni_create_attr_list+0x1e1/0x850 [ 259.216719] kasan_check_range+0x15a/0x1d0 [ 259.216939] memcpy+0x3c/0x70 [ 259.217136] ni_create_attr_list+0x1e1/0x850 [ 259.217945] ? __rcu_read_unlock+0x5b/0x280 [ 259.218384] ? ni_remove_attr+0x2e0/0x2e0 [ 259.218712] ? kernel_text_address+0xcf/0xe0 [ 259.219064] ? __kernel_text_address+0x12/0x40 [ 259.219434] ? arch_stack_walk+0x9e/0xf0 [ 259.219668] ? __this_cpu_preempt_check+0x13/0x20 [ 259.219904] ? sysvec_apic_timer_interrupt+0x57/0xc0 [ 259.220140] ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 [ 259.220561] ni_ins_attr_ext+0x52c/0x5c0 [ 259.220984] ? ni_create_attr_list+0x850/0x850 [ 259.221532] ? run_deallocate+0x120/0x120 [ 259.221972] ? vfs_setxattr+0x128/0x300 [ 259.222688] ? setxattr+0x126/0x140 [ 259.222921] ? path_setxattr+0x164/0x180 [ 259.223431] ? __x64_sys_setxattr+0x6d/0x80 [ 259.223828] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 259.224417] ? mi_find_attr+0x3c/0xf0 [ 259.224772] ni_insert_attr+0x1ba/0x420 [ 259.225216] ? ni_ins_attr_ext+0x5c0/0x5c0 [ 259.225504] ? ntfs_read_ea+0x119/0x450 [ 259.225775] ni_insert_resident+0xc0/0x1c0 [ 259.226316] ? ni_insert_nonresident+0x400/0x400 [ 259.227001] ? __kasan_kmalloc+0x88/0xb0 [ 259.227468] ? __kmalloc+0x192/0x320 [ 259.227773] ntfs_set_ea+0x6bf/0xb30 [ 259.228216] ? ftrace_graph_ret_addr+0x2a/0xb0 [ 259.228494] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 259.228838] ? ntfs_read_ea+0x450/0x450 [ 259.229098] ? is_bpf_text_address+0x24/0x40 [ 259.229418] ? kernel_text_address+0xcf/0xe0 [ 259.229681] ? __kernel_text_address+0x12/0x40 [ 259.229948] ? unwind_get_return_address+0x3a/0x60 [ 259.230271] ? write_profile+0x270/0x270 [ 259.230537] ? arch_stack_walk+0x9e/0xf0 [ 259.230836] ntfs_setxattr+0x114/0x5c0 [ 259.231099] ? ntfs_set_acl_ex+0x2e0/0x2e0 [ 259.231529] ? evm_protected_xattr_common+0x6d/0x100 [ 259.231817] ? posix_xattr_acl+0x13/0x80 [ 259.232073] ? evm_protect_xattr+0x1f7/0x440 [ 259.232351] __vfs_setxattr+0xda/0x120 [ 259.232635] ? xattr_resolve_name+0x180/0x180 [ 259.232912] __vfs_setxattr_noperm+0x93/0x300 [ 259.233219] __vfs_setxattr_locked+0x141/0x160 [ 259.233492] ? kasan_poison+0x3c/0x50 [ 259.233744] vfs_setxattr+0x128/0x300 [ 259.234002] ? __vfs_setxattr_locked+0x160/0x160 [ 259.234837] do_setxattr+0xb8/0x170 [ 259.235567] ? vmemdup_user+0x53/0x90 [ 259.236212] setxattr+0x126/0x140 [ 259.236491] ? do_setxattr+0x170/0x170 [ 259.236791] ? debug_smp_processor_id+0x17/0x20 [ 259.237232] ? kasan_quarantine_put+0x57/0x180 [ 259.237605] ? putname+0x80/0xa0 [ 259.237870] ? __kasan_slab_free+0x11c/0x1b0 [ 259.238234] ? putname+0x80/0xa0 [ 259.238500] ? preempt_count_sub+0x18/0xc0 [ 259.238775] ? __mnt_want_write+0xaa/0x100 [ 259.238990] ? mnt_want_write+0x8b/0x150 [ 259.239290] path_setxattr+0x164/0x180 [ 259.239605] ? setxattr+0x140/0x140 [ 259.239849] ? debug_smp_processor_id+0x17/0x20 [ 259.240174] ? fpregs_assert_state_consistent+0x67/0x80 [ 259.240411] __x64_sys_setxattr+0x6d/0x80 [ 259.240715] do_syscall_64+0x3b/0x90 [ 259.240934] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 259.241697] RIP: 0033:0x7fc6b26e4469 [ 259.242647] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 088 [ 259.244512] RSP: 002b:00007ffc3c7841f8 EFLAGS: 00000217 ORIG_RAX: 00000000000000bc [ 259.245086] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc6b26e4469 [ 259.246025] RDX: 00007ffc3c784380 RSI: 00007ffc3c7842e0 RDI: 00007ffc3c784238 [ 259.246961] RBP: 00007ffc3c788410 R08: 0000000000000001 R09: 00007ffc3c7884f8 [ 259.247775] R10: 000000000000007f R11: 0000000000000217 R12: 00000000004004e0 [ 259.248534] R13: 00007ffc3c7884f0 R14: 0000000000000000 R15: 0000000000000000 [ 259.249368] </TASK> [ 259.249644] [ 259.249888] Allocated by task 255: [ 259.250283] kasan_save_stack+0x26/0x50 [ 259.250957] __kasan_kmalloc+0x88/0xb0 [ 259.251826] __kmalloc+0x192/0x320 [ 259.252745] ni_create_attr_list+0x11e/0x850 [ 259.253298] ni_ins_attr_ext+0x52c/0x5c0 [ 259.253685] ni_insert_attr+0x1ba/0x420 [ 259.253974] ni_insert_resident+0xc0/0x1c0 [ 259.254311] ntfs_set_ea+0x6bf/0xb30 [ 259.254629] ntfs_setxattr+0x114/0x5c0 [ 259.254859] __vfs_setxattr+0xda/0x120 [ 259.255155] __vfs_setxattr_noperm+0x93/0x300 [ 259.255445] __vfs_setxattr_locked+0x141/0x160 [ 259.255862] vfs_setxattr+0x128/0x300 [ 259.256251] do_setxattr+0xb8/0x170 [ 259.256522] setxattr+0x126/0x140 [ 259.256911] path_setxattr+0x164/0x180 [ 259.257308] __x64_sys_setxattr+0x6d/0x80 [ 259.257637] do_syscall_64+0x3b/0x90 [ 259.257970] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 259.258550] [ 259.258772] The buggy address belongs to the object at ffff88800632f000 [ 259.258772] which belongs to the cache kmalloc-1k of size 1024 [ 259.260190] The buggy address is located 690 bytes inside of [ 259.260190] 1024-byte region [ffff88800632f000, ffff88800632f400) [ 259.261412] [ 259.261743] The buggy address belongs to the physical page: [ 259.262354] page:0000000081e8cac9 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x632c [ 259.263722] head:0000000081e8cac9 order:2 compound_mapcount:0 compound_pincount:0 [ 259.264284] flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) [ 259.265312] raw: 000fffffc0010200 ffffea0000060d00 dead000000000004 ffff888001041dc0 [ 259.265772] raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 [ 259.266305] page dumped because: kasan: bad access detected [ 259.266588] [ 259.266728] Memory state around the buggy address: [ 259.267225] ffff88800632f300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 259.267841] ffff88800632f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 259.269111] >ffff88800632f400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 259.269626] ^ [ 259.270162] ffff88800632f480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 259.270810] ffff88800632f500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc Signed-off-by: Edward Lo <edward.lo@ambergroup.io> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
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The quota assign ioctl can currently run in parallel with a quota disable ioctl call. The assign ioctl uses the quota root, while the disable ioctl frees that root, and therefore we can have a use-after-free triggered in the assign ioctl, leading to a trace like the following when KASAN is enabled: [672.723][T736] BUG: KASAN: slab-use-after-free in btrfs_search_slot+0x2962/0x2db0 [672.723][T736] Read of size 8 at addr ffff888022ec0208 by task btrfs_search_sl/27736 [672.724][T736] [672.725][T736] CPU: 1 PID: 27736 Comm: btrfs_search_sl Not tainted 6.3.0-rc3 #37 [672.723][T736] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [672.727][T736] Call Trace: [672.728][T736] <TASK> [672.728][T736] dump_stack_lvl+0xd9/0x150 [672.725][T736] print_report+0xc1/0x5e0 [672.720][T736] ? __virt_addr_valid+0x61/0x2e0 [672.727][T736] ? __phys_addr+0xc9/0x150 [672.725][T736] ? btrfs_search_slot+0x2962/0x2db0 [672.722][T736] kasan_report+0xc0/0xf0 [672.729][T736] ? btrfs_search_slot+0x2962/0x2db0 [672.724][T736] btrfs_search_slot+0x2962/0x2db0 [672.723][T736] ? fs_reclaim_acquire+0xba/0x160 [672.722][T736] ? split_leaf+0x13d0/0x13d0 [672.726][T736] ? rcu_is_watching+0x12/0xb0 [672.723][T736] ? kmem_cache_alloc+0x338/0x3c0 [672.722][T736] update_qgroup_status_item+0xf7/0x320 [672.724][T736] ? add_qgroup_rb+0x3d0/0x3d0 [672.739][T736] ? do_raw_spin_lock+0x12d/0x2b0 [672.730][T736] ? spin_bug+0x1d0/0x1d0 [672.737][T736] btrfs_run_qgroups+0x5de/0x840 [672.730][T736] ? btrfs_qgroup_rescan_worker+0xa70/0xa70 [672.738][T736] ? __del_qgroup_relation+0x4ba/0xe00 [672.738][T736] btrfs_ioctl+0x3d58/0x5d80 [672.735][T736] ? tomoyo_path_number_perm+0x16a/0x550 [672.737][T736] ? tomoyo_execute_permission+0x4a0/0x4a0 [672.731][T736] ? btrfs_ioctl_get_supported_features+0x50/0x50 [672.737][T736] ? __sanitizer_cov_trace_switch+0x54/0x90 [672.734][T736] ? do_vfs_ioctl+0x132/0x1660 [672.730][T736] ? vfs_fileattr_set+0xc40/0xc40 [672.730][T736] ? _raw_spin_unlock_irq+0x2e/0x50 [672.732][T736] ? sigprocmask+0xf2/0x340 [672.737][T736] ? __fget_files+0x26a/0x480 [672.732][T736] ? bpf_lsm_file_ioctl+0x9/0x10 [672.738][T736] ? btrfs_ioctl_get_supported_features+0x50/0x50 [672.736][T736] __x64_sys_ioctl+0x198/0x210 [672.736][T736] do_syscall_64+0x39/0xb0 [672.731][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd [672.739][T736] RIP: 0033:0x4556ad [672.742][T736] </TASK> [672.743][T736] [672.748][T736] Allocated by task 27677: [672.743][T736] kasan_save_stack+0x22/0x40 [672.741][T736] kasan_set_track+0x25/0x30 [672.741][T736] __kasan_kmalloc+0xa4/0xb0 [672.749][T736] btrfs_alloc_root+0x48/0x90 [672.746][T736] btrfs_create_tree+0x146/0xa20 [672.744][T736] btrfs_quota_enable+0x461/0x1d20 [672.743][T736] btrfs_ioctl+0x4a1c/0x5d80 [672.747][T736] __x64_sys_ioctl+0x198/0x210 [672.749][T736] do_syscall_64+0x39/0xb0 [672.744][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd [672.756][T736] [672.757][T736] Freed by task 27677: [672.759][T736] kasan_save_stack+0x22/0x40 [672.759][T736] kasan_set_track+0x25/0x30 [672.756][T736] kasan_save_free_info+0x2e/0x50 [672.751][T736] ____kasan_slab_free+0x162/0x1c0 [672.758][T736] slab_free_freelist_hook+0x89/0x1c0 [672.752][T736] __kmem_cache_free+0xaf/0x2e0 [672.752][T736] btrfs_put_root+0x1ff/0x2b0 [672.759][T736] btrfs_quota_disable+0x80a/0xbc0 [672.752][T736] btrfs_ioctl+0x3e5f/0x5d80 [672.756][T736] __x64_sys_ioctl+0x198/0x210 [672.753][T736] do_syscall_64+0x39/0xb0 [672.765][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd [672.769][T736] [672.768][T736] The buggy address belongs to the object at ffff888022ec0000 [672.768][T736] which belongs to the cache kmalloc-4k of size 4096 [672.769][T736] The buggy address is located 520 bytes inside of [672.769][T736] freed 4096-byte region [ffff888022ec0000, ffff888022ec1000) [672.760][T736] [672.764][T736] The buggy address belongs to the physical page: [672.761][T736] page:ffffea00008bb000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x22ec0 [672.766][T736] head:ffffea00008bb000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 [672.779][T736] flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) [672.770][T736] raw: 00fff00000010200 ffff888012842140 ffffea000054ba00 dead000000000002 [672.770][T736] raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 [672.771][T736] page dumped because: kasan: bad access detected [672.778][T736] page_owner tracks the page as allocated [672.777][T736] page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 88 [672.779][T736] get_page_from_freelist+0x119c/0x2d50 [672.779][T736] __alloc_pages+0x1cb/0x4a0 [672.776][T736] alloc_pages+0x1aa/0x270 [672.773][T736] allocate_slab+0x260/0x390 [672.771][T736] ___slab_alloc+0xa9a/0x13e0 [672.778][T736] __slab_alloc.constprop.0+0x56/0xb0 [672.771][T736] __kmem_cache_alloc_node+0x136/0x320 [672.789][T736] __kmalloc+0x4e/0x1a0 [672.783][T736] tomoyo_realpath_from_path+0xc3/0x600 [672.781][T736] tomoyo_path_perm+0x22f/0x420 [672.782][T736] tomoyo_path_unlink+0x92/0xd0 [672.780][T736] security_path_unlink+0xdb/0x150 [672.788][T736] do_unlinkat+0x377/0x680 [672.788][T736] __x64_sys_unlink+0xca/0x110 [672.789][T736] do_syscall_64+0x39/0xb0 [672.783][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd [672.784][T736] page last free stack trace: [672.787][T736] free_pcp_prepare+0x4e5/0x920 [672.787][T736] free_unref_page+0x1d/0x4e0 [672.784][T736] __unfreeze_partials+0x17c/0x1a0 [672.797][T736] qlist_free_all+0x6a/0x180 [672.796][T736] kasan_quarantine_reduce+0x189/0x1d0 [672.797][T736] __kasan_slab_alloc+0x64/0x90 [672.793][T736] kmem_cache_alloc+0x17c/0x3c0 [672.799][T736] getname_flags.part.0+0x50/0x4e0 [672.799][T736] getname_flags+0x9e/0xe0 [672.792][T736] vfs_fstatat+0x77/0xb0 [672.791][T736] __do_sys_newlstat+0x84/0x100 [672.798][T736] do_syscall_64+0x39/0xb0 [672.796][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd [672.790][T736] [672.791][T736] Memory state around the buggy address: [672.799][T736] ffff888022ec0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [672.805][T736] ffff888022ec0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [672.802][T736] >ffff888022ec0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [672.809][T736] ^ [672.809][T736] ffff888022ec0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [672.809][T736] ffff888022ec0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Fix this by having the qgroup assign ioctl take the qgroup ioctl mutex before calling btrfs_run_qgroups(), which is what all qgroup ioctls should call. Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CAFcO6XN3VD8ogmHwqRk4kbiwtpUSNySu2VAxN8waEPciCHJvMA@mail.gmail.com/ CC: stable@vger.kernel.org # 5.10+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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We encountered a kernel call trace issue which was related to ndo_xdp_xmit callback on our i.MX8MP platform. The reproduce steps show as follows. 1. The FEC port (eth0) connects to a PC port, and the PC uses pktgen_sample03_burst_single_flow.sh to generate packets and send these packets to the FEC port. Notice that the script must be executed before step 2. 2. Run the "./xdp_redirect eth0 eth1" command on i.MX8MP, the eth1 interface is the dwmac. Then there will be a call trace issue soon. Please see the log for more details. The root cause is that the NETDEV_XDP_ACT_NDO_XMIT feature is enabled by default, so when the step 2 command is exexcuted and packets have already been sent to eth0, the stmmac_xdp_xmit() starts running before the stmmac_xdp_set_prog() finishes. To resolve this issue, we disable the NETDEV_XDP_ACT_NDO_XMIT feature by default and turn on/off this feature when the bpf program is installed/uninstalled which just like the other ethernet drivers. Call Trace log: [ 306.311271] ------------[ cut here ]------------ [ 306.315910] WARNING: CPU: 0 PID: 15 at lib/timerqueue.c:55 timerqueue_del+0x68/0x70 [ 306.323590] Modules linked in: [ 306.326654] CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 6.4.0-rc1+ #37 [ 306.333277] Hardware name: NXP i.MX8MPlus EVK board (DT) [ 306.338591] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 306.345561] pc : timerqueue_del+0x68/0x70 [ 306.349577] lr : __remove_hrtimer+0x5c/0xa0 [ 306.353777] sp : ffff80000b7c3920 [ 306.357094] x29: ffff80000b7c3920 x28: 0000000000000000 x27: 0000000000000001 [ 306.364244] x26: ffff80000a763a40 x25: ffff0000d0285a00 x24: 0000000000000001 [ 306.371390] x23: 0000000000000001 x22: ffff000179389a40 x21: 0000000000000000 [ 306.378537] x20: ffff000179389aa0 x19: ffff0000d2951308 x18: 0000000000001000 [ 306.385686] x17: f1d3000000000000 x16: 00000000c39c1000 x15: 55e99bbe00001a00 [ 306.392835] x14: 09000900120aa8c0 x13: e49af1d300000000 x12: 000000000000c39c [ 306.399987] x11: 100055e99bbe0000 x10: ffff8000090b1048 x9 : ffff8000081603fc [ 306.407133] x8 : 000000000000003c x7 : 000000000000003c x6 : 0000000000000001 [ 306.414284] x5 : ffff0000d2950980 x4 : 0000000000000000 x3 : 0000000000000000 [ 306.421432] x2 : 0000000000000001 x1 : ffff0000d2951308 x0 : ffff0000d2951308 [ 306.428585] Call trace: [ 306.431035] timerqueue_del+0x68/0x70 [ 306.434706] __remove_hrtimer+0x5c/0xa0 [ 306.438549] hrtimer_start_range_ns+0x2bc/0x370 [ 306.443089] stmmac_xdp_xmit+0x174/0x1b0 [ 306.447021] bq_xmit_all+0x194/0x4b0 [ 306.450612] __dev_flush+0x4c/0x98 [ 306.454024] xdp_do_flush+0x18/0x38 [ 306.457522] fec_enet_rx_napi+0x6c8/0xc68 [ 306.461539] __napi_poll+0x40/0x220 [ 306.465038] net_rx_action+0xf8/0x240 [ 306.468707] __do_softirq+0x128/0x3a8 [ 306.472378] run_ksoftirqd+0x40/0x58 [ 306.475961] smpboot_thread_fn+0x1c4/0x288 [ 306.480068] kthread+0x124/0x138 [ 306.483305] ret_from_fork+0x10/0x20 [ 306.486889] ---[ end trace 0000000000000000 ]--- Fixes: 66c0e13 ("drivers: net: turn on XDP features") Signed-off-by: Wei Fang <wei.fang@nxp.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Link: https://lore.kernel.org/r/20230524125714.357337-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Aug 11, 2023
Despite commit 0ad529d ("mptcp: fix possible divide by zero in recvmsg()"), the mptcp protocol is still prone to a race between disconnect() (or shutdown) and accept. The root cause is that the mentioned commit checks the msk-level flag, but mptcp_stream_accept() does acquire the msk-level lock, as it can rely directly on the first subflow lock. As reported by Christoph than can lead to a race where an msk socket is accepted after that mptcp_subflow_queue_clean() releases the listener socket lock and just before it takes destructive actions leading to the following splat: BUG: kernel NULL pointer dereference, address: 0000000000000012 PGD 5a4ca067 P4D 5a4ca067 PUD 37d4c067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 2 PID: 10955 Comm: syz-executor.5 Not tainted 6.5.0-rc1-gdc7b257ee5dd #37 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 RIP: 0010:mptcp_stream_accept+0x1ee/0x2f0 include/net/inet_sock.h:330 Code: 0a 09 00 48 8b 1b 4c 39 e3 74 07 e8 bc 7c 7f fe eb a1 e8 b5 7c 7f fe 4c 8b 6c 24 08 eb 05 e8 a9 7c 7f fe 49 8b 85 d8 09 00 00 <0f> b6 40 12 88 44 24 07 0f b6 6c 24 07 bf 07 00 00 00 89 ee e8 89 RSP: 0018:ffffc90000d07dc0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888037e8d020 RCX: ffff88803b093300 RDX: 0000000000000000 RSI: ffffffff833822c5 RDI: ffffffff8333896a RBP: 0000607f82031520 R08: ffff88803b093300 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000003e83 R12: ffff888037e8d020 R13: ffff888037e8c680 R14: ffff888009af7900 R15: ffff888009af6880 FS: 00007fc26d708640(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000012 CR3: 0000000066bc5001 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> do_accept+0x1ae/0x260 net/socket.c:1872 __sys_accept4+0x9b/0x110 net/socket.c:1913 __do_sys_accept4 net/socket.c:1954 [inline] __se_sys_accept4 net/socket.c:1951 [inline] __x64_sys_accept4+0x20/0x30 net/socket.c:1951 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x47/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Address the issue by temporary removing the pending request socket from the accept queue, so that racing accept() can't touch them. After depleting the msk - the ssk still exists, as plain TCP sockets, re-insert them into the accept queue, so that later inet_csk_listen_stop() will complete the tcp socket disposal. Fixes: 2a6a870 ("mptcp: stops worker on unaccepted sockets at listener close") Cc: stable@vger.kernel.org Reported-by: Christoph Paasch <cpaasch@apple.com> Closes: multipath-tcp/mptcp_net-next#423 Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Link: https://lore.kernel.org/r/20230803-upstream-net-20230803-misc-fixes-6-5-v1-4-6671b1ab11cc@tessares.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The mlxbf_gige driver encounters a NULL pointer exception in
mlxbf_gige_open() when kdump is enabled. The sequence to reproduce
the exception is as follows:
a) enable kdump
b) trigger kdump via "echo c > /proc/sysrq-trigger"
c) kdump kernel executes
d) kdump kernel loads mlxbf_gige module
e) the mlxbf_gige module runs its open() as the
the "oob_net0" interface is brought up
f) mlxbf_gige module will experience an exception
during its open(), something like:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000086000004
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000
[0000000000000000] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000086000004 [#1] SMP
CPU: 0 PID: 812 Comm: NetworkManager Tainted: G OE 5.15.0-1035-bluefield #37-Ubuntu
Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024
pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : 0x0
lr : __napi_poll+0x40/0x230
sp : ffff800008003e00
x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff
x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8
x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000
x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000
x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0
x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c
x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398
x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2
x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238
Call trace:
0x0
net_rx_action+0x178/0x360
__do_softirq+0x15c/0x428
__irq_exit_rcu+0xac/0xec
irq_exit+0x18/0x2c
handle_domain_irq+0x6c/0xa0
gic_handle_irq+0xec/0x1b0
call_on_irq_stack+0x20/0x2c
do_interrupt_handler+0x5c/0x70
el1_interrupt+0x30/0x50
el1h_64_irq_handler+0x18/0x2c
el1h_64_irq+0x7c/0x80
__setup_irq+0x4c0/0x950
request_threaded_irq+0xf4/0x1bc
mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige]
mlxbf_gige_open+0x5c/0x170 [mlxbf_gige]
__dev_open+0x100/0x220
__dev_change_flags+0x16c/0x1f0
dev_change_flags+0x2c/0x70
do_setlink+0x220/0xa40
__rtnl_newlink+0x56c/0x8a0
rtnl_newlink+0x58/0x84
rtnetlink_rcv_msg+0x138/0x3c4
netlink_rcv_skb+0x64/0x130
rtnetlink_rcv+0x20/0x30
netlink_unicast+0x2ec/0x360
netlink_sendmsg+0x278/0x490
__sock_sendmsg+0x5c/0x6c
____sys_sendmsg+0x290/0x2d4
___sys_sendmsg+0x84/0xd0
__sys_sendmsg+0x70/0xd0
__arm64_sys_sendmsg+0x2c/0x40
invoke_syscall+0x78/0x100
el0_svc_common.constprop.0+0x54/0x184
do_el0_svc+0x30/0xac
el0_svc+0x48/0x160
el0t_64_sync_handler+0xa4/0x12c
el0t_64_sync+0x1a4/0x1a8
Code: bad PC value
---[ end trace 7d1c3f3bf9d81885 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt
Kernel Offset: 0x2870a7a00000 from 0xffff800008000000
PHYS_OFFSET: 0x80000000
CPU features: 0x0,000005c1,a3332a5a
Memory Limit: none
---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
The exception happens because there is a pending RX interrupt before the
call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires
immediately after this request_irq() completes. The RX IRQ handler runs
"napi_schedule()" before NAPI is fully initialized via "netif_napi_add()"
and "napi_enable()", both which happen later in the open() logic.
The logic in mlxbf_gige_open() must fully initialize NAPI before any calls
to request_irq() execute.
Fixes: f92e186 ("Add Mellanox BlueField Gigabit Ethernet driver")
Signed-off-by: David Thompson <davthompson@nvidia.com>
Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Link: https://lore.kernel.org/r/20240325183627.7641-1-davthompson@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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__kernel_map_pages() is a debug function which clears the valid bit in page table entry for deallocated pages to detect illegal memory accesses to freed pages. This function set/clear the valid bit using __set_memory(). __set_memory() acquires init_mm's semaphore, and this operation may sleep. This is problematic, because __kernel_map_pages() can be called in atomic context, and thus is illegal to sleep. An example warning that this causes: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd preempt_count: 2, expected: 0 CPU: 0 PID: 2 Comm: kthreadd Not tainted 6.9.0-g1d4c6d784ef6 #37 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff800060dc>] dump_backtrace+0x1c/0x24 [<ffffffff8091ef6e>] show_stack+0x2c/0x38 [<ffffffff8092baf8>] dump_stack_lvl+0x5a/0x72 [<ffffffff8092bb24>] dump_stack+0x14/0x1c [<ffffffff8003b7ac>] __might_resched+0x104/0x10e [<ffffffff8003b7f4>] __might_sleep+0x3e/0x62 [<ffffffff8093276a>] down_write+0x20/0x72 [<ffffffff8000cf00>] __set_memory+0x82/0x2fa [<ffffffff8000d324>] __kernel_map_pages+0x5a/0xd4 [<ffffffff80196cca>] __alloc_pages_bulk+0x3b2/0x43a [<ffffffff8018ee82>] __vmalloc_node_range+0x196/0x6ba [<ffffffff80011904>] copy_process+0x72c/0x17ec [<ffffffff80012ab4>] kernel_clone+0x60/0x2fe [<ffffffff80012f62>] kernel_thread+0x82/0xa0 [<ffffffff8003552c>] kthreadd+0x14a/0x1be [<ffffffff809357de>] ret_from_fork+0xe/0x1c Rewrite this function with apply_to_existing_page_range(). It is fine to not have any locking, because __kernel_map_pages() works with pages being allocated/deallocated and those pages are not changed by anyone else in the meantime. Fixes: 5fde3db ("riscv: add ARCH_SUPPORTS_DEBUG_PAGEALLOC support") Signed-off-by: Nam Cao <namcao@linutronix.de> Cc: stable@vger.kernel.org Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/1289ecba9606a19917bc12b6c27da8aa23e1e5ae.1715750938.git.namcao@linutronix.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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While validating node ids in map_benchmark_ioctl(), node_possible() may be provided with invalid argument outside of [0,MAX_NUMNODES-1] range leading to: BUG: KASAN: wild-memory-access in map_benchmark_ioctl (kernel/dma/map_benchmark.c:214) Read of size 8 at addr 1fffffff8ccb6398 by task dma_map_benchma/971 CPU: 7 PID: 971 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #37 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:117) kasan_report (mm/kasan/report.c:603) kasan_check_range (mm/kasan/generic.c:189) variable_test_bit (arch/x86/include/asm/bitops.h:227) [inline] arch_test_bit (arch/x86/include/asm/bitops.h:239) [inline] _test_bit at (include/asm-generic/bitops/instrumented-non-atomic.h:142) [inline] node_state (include/linux/nodemask.h:423) [inline] map_benchmark_ioctl (kernel/dma/map_benchmark.c:214) full_proxy_unlocked_ioctl (fs/debugfs/file.c:333) __x64_sys_ioctl (fs/ioctl.c:890) do_syscall_64 (arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Compare node ids with sane bounds first. NUMA_NO_NODE is considered a special valid case meaning that benchmarking kthreads won't be bound to a cpuset of a given node. Found by Linux Verification Center (linuxtesting.org). Fixes: 65789da ("dma-mapping: add benchmark support for streaming DMA APIs") Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
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May 28, 2025
ACPICA commit 1c28da2242783579d59767617121035dafba18c3 This was originally done in NetBSD: NetBSD/src@b69d1ac and is the correct alternative to the smattering of `memcpy`s I previously contributed to this repository. This also sidesteps the newly strict checks added in UBSAN: llvm/llvm-project@7926744 Before this change we see the following UBSAN stack trace in Fuchsia: #0 0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e #1.2 0x000021982bc4af3c in ubsan_get_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:41 <libclang_rt.asan.so>+0x41f3c #1.1 0x000021982bc4af3c in maybe_print_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:51 <libclang_rt.asan.so>+0x41f3c #1 0x000021982bc4af3c in ~scoped_report() compiler-rt/lib/ubsan/ubsan_diag.cpp:395 <libclang_rt.asan.so>+0x41f3c #2 0x000021982bc4bb6f in handletype_mismatch_impl() compiler-rt/lib/ubsan/ubsan_handlers.cpp:137 <libclang_rt.asan.so>+0x42b6f #3 0x000021982bc4b723 in __ubsan_handle_type_mismatch_v1 compiler-rt/lib/ubsan/ubsan_handlers.cpp:142 <libclang_rt.asan.so>+0x42723 #4 0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e #5 0x000021afcfdf2089 in acpi_rs_convert_aml_to_resource(struct acpi_resource*, union aml_resource*, struct acpi_rsconvert_info*) ../../third_party/acpica/source/components/resources/rsmisc.c:355 <platform-bus-x86.so>+0x6b2089 #6 0x000021afcfded169 in acpi_rs_convert_aml_to_resources(u8*, u32, u32, u8, void**) ../../third_party/acpica/source/components/resources/rslist.c:137 <platform-bus-x86.so>+0x6ad169 #7 0x000021afcfe2d24a in acpi_ut_walk_aml_resources(struct acpi_walk_state*, u8*, acpi_size, acpi_walk_aml_callback, void**) ../../third_party/acpica/source/components/utilities/utresrc.c:237 <platform-bus-x86.so>+0x6ed24a #8 0x000021afcfde66b7 in acpi_rs_create_resource_list(union acpi_operand_object*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rscreate.c:199 <platform-bus-x86.so>+0x6a66b7 #9 0x000021afcfdf6979 in acpi_rs_get_method_data(acpi_handle, const char*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rsutils.c:770 <platform-bus-x86.so>+0x6b6979 #10 0x000021afcfdf708f in acpi_walk_resources(acpi_handle, char*, acpi_walk_resource_callback, void*) ../../third_party/acpica/source/components/resources/rsxface.c:731 <platform-bus-x86.so>+0x6b708f #11 0x000021afcfa95dcf in acpi::acpi_impl::walk_resources(acpi::acpi_impl*, acpi_handle, const char*, acpi::Acpi::resources_callable) ../../src/devices/board/lib/acpi/acpi-impl.cc:41 <platform-bus-x86.so>+0x355dcf #12 0x000021afcfaa8278 in acpi::device_builder::gather_resources(acpi::device_builder*, acpi::Acpi*, fidl::any_arena&, acpi::Manager*, acpi::device_builder::gather_resources_callback) ../../src/devices/board/lib/acpi/device-builder.cc:84 <platform-bus-x86.so>+0x368278 #13 0x000021afcfbddb87 in acpi::Manager::configure_discovered_devices(acpi::Manager*) ../../src/devices/board/lib/acpi/manager.cc:75 <platform-bus-x86.so>+0x49db87 #14 0x000021afcf99091d in publish_acpi_devices(acpi::Manager*, zx_device_t*, zx_device_t*) ../../src/devices/board/drivers/x86/acpi-nswalk.cc:95 <platform-bus-x86.so>+0x25091d #15 0x000021afcf9c1d4e in x86::X86::do_init(x86::X86*) ../../src/devices/board/drivers/x86/x86.cc:60 <platform-bus-x86.so>+0x281d4e #16 0x000021afcf9e33ad in λ(x86::X86::ddk_init::(anon class)*) ../../src/devices/board/drivers/x86/x86.cc:77 <platform-bus-x86.so>+0x2a33ad #17 0x000021afcf9e313e in fit::internal::target<(lambda at../../src/devices/board/drivers/x86/x86.cc:76:19), false, false, std::__2::allocator<std::byte>, void>::invoke(void*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:183 <platform-bus-x86.so>+0x2a313e #18 0x000021afcfbab4c7 in fit::internal::function_base<16UL, false, void(), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <platform-bus-x86.so>+0x46b4c7 #19 0x000021afcfbab342 in fit::function_impl<16UL, false, void(), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/function.h:315 <platform-bus-x86.so>+0x46b342 #20 0x000021afcfcd98c3 in async::internal::retained_task::Handler(async_dispatcher_t*, async_task_t*, zx_status_t) ../../sdk/lib/async/task.cc:24 <platform-bus-x86.so>+0x5998c3 #21 0x00002290f9924616 in λ(const driver_runtime::Dispatcher::post_task::(anon class)*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/dispatcher.cc:789 <libdriver_runtime.so>+0x10a616 #22 0x00002290f9924323 in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:788:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int>::invoke(void*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0x10a323 #23 0x00002290f9904b76 in fit::internal::function_base<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xeab76 #24 0x00002290f9904831 in fit::callback_impl<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::operator()(fit::callback_impl<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/function.h:471 <libdriver_runtime.so>+0xea831 #25 0x00002290f98d5adc in driver_runtime::callback_request::Call(driver_runtime::callback_request*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/callback_request.h:74 <libdriver_runtime.so>+0xbbadc #26 0x00002290f98e1e58 in driver_runtime::Dispatcher::dispatch_callback(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >) ../../src/devices/bin/driver_runtime/dispatcher.cc:1248 <libdriver_runtime.so>+0xc7e58 #27 0x00002290f98e4159 in driver_runtime::Dispatcher::dispatch_callbacks(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:1308 <libdriver_runtime.so>+0xca159 #28 0x00002290f9918414 in λ(const driver_runtime::Dispatcher::create_with_adder::(anon class)*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:353 <libdriver_runtime.so>+0xfe414 #29 0x00002290f991812d in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:351:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>>::invoke(void*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0xfe12d #30 0x00002290f9906fc7 in fit::internal::function_base<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xecfc7 #31 0x00002290f9906c66 in fit::function_impl<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/function.h:315 <libdriver_runtime.so>+0xecc66 #32 0x00002290f98e73d9 in driver_runtime::Dispatcher::event_waiter::invoke_callback(driver_runtime::Dispatcher::event_waiter*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.h:543 <libdriver_runtime.so>+0xcd3d9 #33 0x00002290f98e700d in driver_runtime::Dispatcher::event_waiter::handle_event(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/dispatcher.cc:1442 <libdriver_runtime.so>+0xcd00d #34 0x00002290f9918983 in async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event(async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>*, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/async_loop_owned_event_handler.h:59 <libdriver_runtime.so>+0xfe983 #35 0x00002290f9918b9e in async::wait_method<async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>, &async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event>::call_handler(async_dispatcher_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async/include/lib/async/cpp/wait.h:201 <libdriver_runtime.so>+0xfeb9e #36 0x00002290f99bf509 in async_loop_dispatch_wait(async_loop_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async-loop/loop.c:394 <libdriver_runtime.so>+0x1a5509 #37 0x00002290f99b9958 in async_loop_run_once(async_loop_t*, zx_time_t) ../../sdk/lib/async-loop/loop.c:343 <libdriver_runtime.so>+0x19f958 #38 0x00002290f99b9247 in async_loop_run(async_loop_t*, zx_time_t, _Bool) ../../sdk/lib/async-loop/loop.c:301 <libdriver_runtime.so>+0x19f247 #39 0x00002290f99ba962 in async_loop_run_thread(void*) ../../sdk/lib/async-loop/loop.c:860 <libdriver_runtime.so>+0x1a0962 #40 0x000041afd176ef30 in start_c11(void*) ../../zircon/third_party/ulib/musl/pthread/pthread_create.c:63 <libc.so>+0x84f30 #41 0x000041afd18a448d in thread_trampoline(uintptr_t, uintptr_t) ../../zircon/system/ulib/runtime/thread.cc:100 <libc.so>+0x1ba48d Link: acpica/acpica@1c28da22 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://patch.msgid.link/4664267.LvFx2qVVIh@rjwysocki.net Signed-off-by: Tamir Duberstein <tamird@gmail.com> [ rjw: Pick up the tag from Tamir ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Aug 9, 2025
A kernel panic can be triggered by reading /proc/fs/cifs/debug_dirs.
The crash is a null-ptr-deref inside spin_lock(), caused by the use of the
uninitialized global spinlock cifs_tcp_ses_lock.
init_cifs()
└── cifs_proc_init()
└── // User can access /proc/fs/cifs/debug_dirs here
└── cifs_debug_dirs_proc_show()
└── spin_lock(&cifs_tcp_ses_lock); // Uninitialized!
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Mem abort info:
ESR = 0x0000000096000005
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x05: level 1 translation fault
Data abort info:
ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] SMP
Modules linked in:
CPU: 3 UID: 0 PID: 16435 Comm: stress-ng-procf Not tainted 6.16.0-10385-g79f14b5d84c6 #37 PREEMPT
Hardware name: QEMU KVM Virtual Machine, BIOS 2025.02-8ubuntu1 06/11/2025
pstate: 23400005 (nzCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : do_raw_spin_lock+0x84/0x2cc
lr : _raw_spin_lock+0x24/0x34
sp : ffff8000966477e0
x29: ffff800096647860 x28: ffff800096647b88 x27: ffff0001c0c22070
x26: ffff0003eb2b60c8 x25: ffff0001c0c22018 x24: dfff800000000000
x23: ffff0000f624e000 x22: ffff0003eb2b6020 x21: ffff0000f624e768
x20: 0000000000000004 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000804b9600 x15: ffff700012cc8f04
x14: 1ffff00012cc8f04 x13: 0000000000000004 x12: ffffffffffffffff
x11: 1ffff00012cc8f00 x10: ffff80008d9af0d2 x9 : f3f3f304f1f1f1f1
x8 : 0000000000000000 x7 : 7365733c203e6469 x6 : 20656572743c2023
x5 : ffff0000e0ce0044 x4 : ffff80008a4deb6e x3 : ffff8000804b9718
x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
do_raw_spin_lock+0x84/0x2cc (P)
_raw_spin_lock+0x24/0x34
cifs_debug_dirs_proc_show+0x1ac/0x4c0
seq_read_iter+0x3b0/0xc28
proc_reg_read_iter+0x178/0x2a8
vfs_read+0x5f8/0x88c
ksys_read+0x120/0x210
__arm64_sys_read+0x7c/0x90
invoke_syscall+0x98/0x2b8
el0_svc_common+0x130/0x23c
do_el0_svc+0x48/0x58
el0_svc+0x40/0x140
el0t_64_sync_handler+0x84/0x12c
el0t_64_sync+0x1ac/0x1b0
Code: aa0003f3 f9000feb f2fe7e69 f8386969 (38f86908)
---[ end trace 0000000000000000 ]---
The root cause is an initialization order problem. The lock is declared
as a global variable and intended to be initialized during module startup.
However, the procfs entry that uses this lock can be accessed by userspace
before the spin_lock_init() call has run. This creates a race window where
reading the proc file will attempt to use the lock before it is
initialized, leading to the crash.
For a global lock with a static lifetime, the correct and robust approach
is to use compile-time initialization.
Fixes: 844e5c0 ("smb3 client: add way to show directory leases for improved debugging")
Signed-off-by: Yunseong Kim <ysk@kzalloc.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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