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tmlind and others added 30 commits August 19, 2020 18:16
Fix warnings for omap_gpio_resume and omap_gpio_suspend
defined but not used when PM is disabled as noticed when
doing make randconfig builds.

Fixes: f02a039 ("gpio: omap: Add missing PM ops for suspend")
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
The raw interrupt status of GPIO maybe set before the interrupt is enabled,
which would trigger the interrupt event once enabled it from user side.
This is the case for edge interrupts only. Adding a clear operation when
setting interrupt type can avoid that.

There're a few considerations for the solution:
1) This issue is for edge interrupt only; The interrupts requested by users
   are IRQ_TYPE_LEVEL_HIGH as default, so clearing interrupt when request
   is useless.
2) The interrupt type can be set to edge when request and following up
   with clearing it though, but the problem is still there once users set
   the interrupt type to level trggier.
3) We can add a clear operation after each time of setting interrupt
   enable bit, but it is redundant for level trigger interrupt.

Therefore, the solution is this patch seems the best for now.

Fixes: 9a3821c ("gpio: Add GPIO driver for Spreadtrum SC9860 platform")
Signed-off-by: Taiping Lai <taiping.lai@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
The offset of regmap is incorrect, j * 8 is move to the
wrong register.

for example:

asume i = 0, j = 1. we want to set KPY5 as interrupt
falling edge mode, regmap[0][1] should be TC3589x_GPIOIBE1 0xcd
but, regmap[i] + j * 8 = TC3589x_GPIOIBE0 + 8 ,point to 0xd4,
this is TC3589x_GPIOIE2 not TC3589x_GPIOIBE1.

Fixes: d88b25b ("gpio: Add TC35892 GPIO driver")
Cc: Cc: stable@vger.kernel.org
Signed-off-by: dillon min <dillon.minfei@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
The gpio-siox driver uses handle_nested_irq() to implement its
interrupt support. This is only capable of handling threaded irq
actions. For a hardirq action it triggers a NULL pointer oops.
(It calls action->thread_fn which is NULL then.)

Prevent registration of a hardirq action by setting
gpio_irq_chip::threaded to true.

Cc: u.kleine-koenig@pengutronix.de
Fixes: be8c8fa ("gpio: new driver to work with a 8x12 siox")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
If the module init function fails after creating the debugs directory,
it's never removed. Add proper cleanup calls to avoid this resource
leak.

Fixes: 9202ba2 ("gpio: mockup: implement event injecting over debugfs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
removes the need to clear it, along with the races.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Checking for the lack of epitems refering to the epoll we want to insert into
is not enough; we might have an insertion of that epoll into another one that
has already collected the set of files to recheck for excessive reverse paths,
but hasn't gotten to creating/inserting the epitem for it.

However, any such insertion in progress can be detected - it will update the
generation count in our epoll when it's done looking through it for files
to check.  That gets done under ->mtx of our epoll and that allows us to
detect that safely.

We are *not* holding epmutex here, so the generation count is not stable.
However, since both the update of ep->gen by loop check and (later)
insertion into ->f_ep_link are done with ep->mtx held, we are fine -
the sequence is
	grab epmutex
	bump loop_check_gen
	...
	grab tep->mtx		// 1
	tep->gen = loop_check_gen
	...
	drop tep->mtx		// 2
	...
	grab tep->mtx		// 3
	...
	insert into ->f_ep_link
	...
	drop tep->mtx		// 4
	bump loop_check_gen
	drop epmutex
and if the fastpath check in another thread happens for that
eventpoll, it can come
	* before (1) - in that case fastpath is just fine
	* after (4) - we'll see non-empty ->f_ep_link, slow path
taken
	* between (2) and (3) - loop_check_gen is stable,
with ->mtx providing barriers and we end up taking slow path.

Note that ->f_ep_link emptiness check is slightly racy - we are protected
against insertions into that list, but removals can happen right under us.
Not a problem - in the worst case we'll end up taking a slow path for
no good reason.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
…inux/kernel/git/brgl/linux into fixes

gpio fixes for v5.9-rc4

- fix warnings if PM is enabled in gpio-omap
- clear interrupt when setting the type as edge in gpio-sprd
The introduced line event handling ABI in the commit

  61f922d ("gpio: userspace ABI for reading GPIO line events")

missed the fact that 64-bit kernel may serve for 32-bit applications.
In such case the very first check in the lineevent_read() will fail
due to alignment differences.

To workaround this introduce lineevent_get_size() helper which returns actual
size of the structure in user space.

Fixes: 61f922d ("gpio: userspace ABI for reading GPIO line events")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This patch fixes the device name typo.

Fixes: 951ad47 ("iio: adc: ad7124: move chip ID & name on the chip_info table")
Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200902134222.28357-1-mircea.caprioru@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
…inux/kernel/git/brgl/linux into fixes

gpio fixes for v5.9-rc6

- fix the interrupt configuration in gpio-tc35894
- explicitly support only threaded irqs in gpio-siox
- fix a resource leak in error path in gpio-mockup
- fix line event handling in syscall compatible mode in GPIO chardev
Remove superfluous '.c' from qcom-spmi-adc5 device driver name.
Fixes: e13d757 ("iio: adc: Add QCOM SPMI PMIC5 ADC driver")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200910140000.324091-2-dmitry.baryshkov@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
…m/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

2nd set of IIO fixes for the 5.9 cycle.

One of these fixes a regresison introduced this cycle, but if I am too late
sending this request, it can be queued up for the merge window.

ad7124: fix typo in device name exposed through sysfs.
qcom-spmi-adc: fix stray .c in driver name field.

* tag 'iio-fixes-for-5.9b-take2' of https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio:
  iio: adc: qcom-spmi-adc5: fix driver name
  iio: adc: ad7124: Fix typo in device name
When pca953x_irq_pending returns false, the pending parameter won't
be set. But pca953x_irq_handler continues using this uninitialized
variable as pending irqs and will cause problem.
Fix the issue by initializing pending to 0.

Fixes: 064c73a ("gpio: pca953x: Synchronize interrupt handler properly")
Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Currently, the aspeed-sgpio driver exposes up to 80 GPIO lines,
corresponding to the 80 status bits available in hardware. Each of these
lines can be configured as either an input or an output.

However, each of these GPIOs is actually an input *and* an output; we
actually have 80 inputs plus 80 outputs.

This change expands the maximum number of GPIOs to 160; the lower half
of this range are the input-only GPIOs, the upper half are the outputs.
We fix the GPIO directions to correspond to this mapping.

This also fixes a bug when setting GPIOs - we were reading from the
input register, making it impossible to set more than one output GPIO.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Fixes: 7db47fa ("gpio: aspeed: Add SGPIO driver")
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Currently, the IRQ setup for the SGPIO driver enables all interrupts in
dual-edge trigger mode. Since the default handler is handle_bad_irq, any
state change on input GPIOs will trigger bad IRQ warnings.

This change applies sensible IRQ defaults: single-edge trigger, and all
IRQs disabled.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Fixes: 7db47fa ("gpio: aspeed: Add SGPIO driver")
Reviewed-by: Joel Stanley <joel@jms.id.au>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
GPIO_U is mapped to the least significant byte of input/output mask, and
the byte in "output" mask should be 0 because GPIO_U is input only. All
the other bits need to be 1 because GPIO_V/W/X support both input and
output modes.

Similarly, GPIO_Y/Z are mapped to the 2 least significant bytes, and the
according bits need to be 1 because GPIO_Y/Z support both input and
output modes.

Fixes: ab4a855 ("gpio: aspeed: Add in ast2600 details to Aspeed driver")
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
or get freed, for that matter, if it's a long (separately stored)
name.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We need to move the closing of the src_device out of all the device
replace locking, but we definitely want to zero out the superblock
before we commit the last time to make sure the device is properly
removed.  Handle this by pushing btrfs_scratch_superblocks into
btrfs_dev_replace_finishing, and then later on we'll move the src_device
closing and freeing stuff where we need it to be.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
After commit 6827ca5 ("memstick: rtsx_usb_ms: Support runtime power
management"), removing module rtsx_usb_ms will be stuck.

The deadlock is caused by powering on and powering off at the same time,
the former one is when memstick_check() is flushed, and the later is called
by memstick_remove_host().

Soe let's skip allocating card to prevent this issue.

Fixes: 6827ca5 ("memstick: rtsx_usb_ms: Support runtime power management")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20200925084952.13220-1-kai.heng.feng@canonical.com
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
…S models

Commit bedf9fc ("mmc: sdhci: Workaround broken command queuing on
Intel GLK"), disabled command-queuing on Intel GLK based LENOVO models
because of it being broken due to what is believed to be a bug in
the BIOS.

It seems that the BIOS of some IRBIS models, including the IRBIS NB111
model has the same issue, so disable command queuing there too.

Fixes: bedf9fc ("mmc: sdhci: Workaround broken command queuing on Intel GLK")
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209397
Reported-and-tested-by: RussianNeuroMancer <russianneuromancer@ya.ru>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200927104821.5676-1-hdegoede@redhat.com
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The original commit appears to have the logic reversed in
amd_fch_gpio_get_direction. Also confirmed by observing the value of
"direction" in the sys tree.

Signed-off-by: Ed Wildgoose <lists@wildgooses.com>
Fixes: e09d168 ("gpio: AMD G-Series PCH gpio driver")
Cc: stable@vger.kernel.org
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
…inux/kernel/git/brgl/linux into fixes

gpio: fixes for v5.9-rc7

- fix uninitialized variable in gpio-pca953x
- enable all 160 lines and fix interrupt configuration in gpio-aspeed-gpio
- fix ast2600 bank properties in gpio-aspeed
clint_time_val will soon be used by the RISC-V implementation of
random_get_entropy(), which is a static inline function that may be used by
modules (at least CRYPTO_JITTERENTROPY=m).

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
…/kernel/git/brgl/linux into fixes

gpio fixes for v5.9

- correct logic of GPIO_LINE_DIRECTION in gpio-amd-fch
Fix missing return statement when writing "off" to intel_pstate status
sysfs I/F.

Fixes: 55671ea ("cpufreq: intel_pstate: Free memory only when turning off")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix a reStructuredText syntax error in the cpuidle PM admin-guide
documentation: the ``...'' quotation marks are parsed as partial ''...''
reStructuredText markup and break the output formatting.

This change them to "...".

Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The commit eb1f002 ("lockdep,trace: Expose tracepoints"), started to
expose us for tracepoints. For imx6q cpuidle, this leads to an RCU splat
according to below.

[6.870684] [<c0db7690>] (_raw_spin_lock) from [<c011f6a4>] (imx6q_enter_wait+0x18/0x9c)
[6.878846] [<c011f6a4>] (imx6q_enter_wait) from [<c09abfb0>] (cpuidle_enter_state+0x168/0x5e4)

To fix the problem, let's assign the corresponding idlestate->flags the
CPUIDLE_FLAG_RCU_IDLE bit, which enables us to call rcu_idle_enter|exit()
at the proper point.

Reported-by: Dong Aisheng <aisheng.dong@nxp.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex.  As such
we want to be holding as few locks as possible, so move this call
outside of the dev_replace->lock_finishing_cancel_unmount lock.  Since
we're modifying the fs_devices we need to make sure we're holding the
uuid_mutex here, so take that as well.

There's a report from syzbot probably hitting one of the cases where
the bd_mutex and device_list_mutex are taken in the wrong order, however
it's not with device replace, like this patch fixes. As there's no
reproducer available so far, we can't verify the fix.

https://lore.kernel.org/lkml/000000000000fc04d105afcf86d7@google.com/
dashboard link: https://syzkaller.appspot.com/bug?extid=84a0634dc5d21d488419

  WARNING: possible circular locking dependency detected
  5.9.0-rc5-syzkaller #0 Not tainted
  ------------------------------------------------------
  syz-executor.0/6878 is trying to acquire lock:
  ffff88804c17d780 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x30/0x520 fs/block_dev.c:1804

  but task is already holding lock:
  ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 btrfs_finish_chunk_alloc+0x281/0xf90 fs/btrfs/volumes.c:5255
	 btrfs_create_pending_block_groups+0x2f3/0x700 fs/btrfs/block-group.c:2109
	 __btrfs_end_transaction+0xf5/0x690 fs/btrfs/transaction.c:916
	 find_free_extent_update_loop fs/btrfs/extent-tree.c:3807 [inline]
	 find_free_extent+0x23b7/0x2e60 fs/btrfs/extent-tree.c:4127
	 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
	 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
	 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
	 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
	 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
	 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
	 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
	 do_writepages+0xec/0x290 mm/page-writeback.c:2352
	 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
	 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
	 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
	 wb_do_writeback fs/fs-writeback.c:2039 [inline]
	 wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
	 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
	 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
	 kthread+0x3b5/0x4a0 kernel/kthread.c:292
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

  -> #3 (sb_internal#2){.+.+}-{0:0}:
	 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
	 __sb_start_write+0x234/0x470 fs/super.c:1672
	 sb_start_intwrite include/linux/fs.h:1690 [inline]
	 start_transaction+0xbe7/0x1170 fs/btrfs/transaction.c:624
	 find_free_extent_update_loop fs/btrfs/extent-tree.c:3789 [inline]
	 find_free_extent+0x25e1/0x2e60 fs/btrfs/extent-tree.c:4127
	 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
	 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
	 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
	 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
	 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
	 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
	 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
	 do_writepages+0xec/0x290 mm/page-writeback.c:2352
	 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
	 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
	 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
	 wb_do_writeback fs/fs-writeback.c:2039 [inline]
	 wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
	 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
	 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
	 kthread+0x3b5/0x4a0 kernel/kthread.c:292
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

  -> #2 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
	 __flush_work+0x60e/0xac0 kernel/workqueue.c:3041
	 wb_shutdown+0x180/0x220 mm/backing-dev.c:355
	 bdi_unregister+0x174/0x590 mm/backing-dev.c:872
	 del_gendisk+0x820/0xa10 block/genhd.c:933
	 loop_remove drivers/block/loop.c:2192 [inline]
	 loop_control_ioctl drivers/block/loop.c:2291 [inline]
	 loop_control_ioctl+0x3b1/0x480 drivers/block/loop.c:2257
	 vfs_ioctl fs/ioctl.c:48 [inline]
	 __do_sys_ioctl fs/ioctl.c:753 [inline]
	 __se_sys_ioctl fs/ioctl.c:739 [inline]
	 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
	 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (loop_ctl_mutex){+.+.}-{3:3}:
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 lo_open+0x19/0xd0 drivers/block/loop.c:1893
	 __blkdev_get+0x759/0x1aa0 fs/block_dev.c:1507
	 blkdev_get fs/block_dev.c:1639 [inline]
	 blkdev_open+0x227/0x300 fs/block_dev.c:1753
	 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
	 do_open fs/namei.c:3251 [inline]
	 path_openat+0x1b9a/0x2730 fs/namei.c:3368
	 do_filp_open+0x17e/0x3c0 fs/namei.c:3395
	 do_sys_openat2+0x16d/0x420 fs/open.c:1168
	 do_sys_open fs/open.c:1184 [inline]
	 __do_sys_open fs/open.c:1192 [inline]
	 __se_sys_open fs/open.c:1188 [inline]
	 __x64_sys_open+0x119/0x1c0 fs/open.c:1188
	 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&bdev->bd_mutex){+.+.}-{3:3}:
	 check_prev_add kernel/locking/lockdep.c:2496 [inline]
	 check_prevs_add kernel/locking/lockdep.c:2601 [inline]
	 validate_chain kernel/locking/lockdep.c:3218 [inline]
	 __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
	 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 blkdev_put+0x30/0x520 fs/block_dev.c:1804
	 btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
	 btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
	 btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
	 close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
	 close_fs_devices fs/btrfs/volumes.c:1193 [inline]
	 btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
	 close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
	 generic_shutdown_super+0x144/0x370 fs/super.c:464
	 kill_anon_super+0x36/0x60 fs/super.c:1108
	 btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
	 deactivate_locked_super+0x94/0x160 fs/super.c:335
	 deactivate_super+0xad/0xd0 fs/super.c:366
	 cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
	 task_work_run+0xdd/0x190 kernel/task_work.c:141
	 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
	 exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
	 exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
	 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &bdev->bd_mutex --> sb_internal#2 --> &fs_devs->device_list_mutex

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_devs->device_list_mutex);
				 lock(sb_internal#2);
				 lock(&fs_devs->device_list_mutex);
    lock(&bdev->bd_mutex);

   *** DEADLOCK ***

  3 locks held by syz-executor.0/6878:
   #0: ffff88809070c0e0 (&type->s_umount_key#70){++++}-{3:3}, at: deactivate_super+0xa5/0xd0 fs/super.c:365
   #1: ffffffff8a5b37a8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_close_devices+0x23/0x1f0 fs/btrfs/volumes.c:1178
   #2: ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

  stack backtrace:
  CPU: 0 PID: 6878 Comm: syz-executor.0 Not tainted 5.9.0-rc5-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:77 [inline]
   dump_stack+0x198/0x1fd lib/dump_stack.c:118
   check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827
   check_prev_add kernel/locking/lockdep.c:2496 [inline]
   check_prevs_add kernel/locking/lockdep.c:2601 [inline]
   validate_chain kernel/locking/lockdep.c:3218 [inline]
   __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
   lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
   __mutex_lock_common kernel/locking/mutex.c:956 [inline]
   __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
   blkdev_put+0x30/0x520 fs/block_dev.c:1804
   btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
   btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
   btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
   close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
   close_fs_devices fs/btrfs/volumes.c:1193 [inline]
   btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
   close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
   generic_shutdown_super+0x144/0x370 fs/super.c:464
   kill_anon_super+0x36/0x60 fs/super.c:1108
   btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
   deactivate_locked_super+0x94/0x160 fs/super.c:335
   deactivate_super+0xad/0xd0 fs/super.c:366
   cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
   task_work_run+0xdd/0x190 kernel/task_work.c:141
   tracehook_notify_resume include/linux/tracehook.h:188 [inline]
   exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
   exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
   syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x460027
  RSP: 002b:00007fff59216328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  RAX: 0000000000000000 RBX: 0000000000076035 RCX: 0000000000460027
  RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fff592163d0
  RBP: 0000000000000333 R08: 0000000000000000 R09: 000000000000000b
  R10: 0000000000000005 R11: 0000000000000246 R12: 00007fff59217460
  R13: 0000000002df2a60 R14: 0000000000000000 R15: 00007fff59217460

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add syzbot reference ]
Signed-off-by: David Sterba <dsterba@suse.com>
fdmanana and others added 14 commits September 30, 2020 19:40
We use a device's allocation state tree to track ranges in a device used
for allocated chunks, and we set ranges in this tree when allocating a new
chunk. However after a device replace operation, we were not setting the
allocated ranges in the new device's allocation state tree, so that tree
is empty after a device replace.

This means that a fitrim operation after a device replace will trim the
device ranges that have allocated chunks and extents, as we trim every
range for which there is not a range marked in the device's allocation
state tree. It is also important during chunk allocation, since the
device's allocation state is used to determine if a range is already
allocated when allocating a new chunk.

This is trivial to reproduce and the following script triggers the bug:

  $ cat reproducer.sh
  #!/bin/bash

  DEV1="/dev/sdg"
  DEV2="/dev/sdh"
  DEV3="/dev/sdi"

  wipefs -a $DEV1 $DEV2 $DEV3 &> /dev/null

  # Create a raid1 test fs on 2 devices.
  mkfs.btrfs -f -m raid1 -d raid1 $DEV1 $DEV2 > /dev/null
  mount $DEV1 /mnt/btrfs

  xfs_io -f -c "pwrite -S 0xab 0 10M" /mnt/btrfs/foo

  echo "Starting to replace $DEV1 with $DEV3"
  btrfs replace start -B $DEV1 $DEV3 /mnt/btrfs
  echo

  echo "Running fstrim"
  fstrim /mnt/btrfs
  echo

  echo "Unmounting filesystem"
  umount /mnt/btrfs

  echo "Mounting filesystem in degraded mode using $DEV3 only"
  wipefs -a $DEV1 $DEV2 &> /dev/null
  mount -o degraded $DEV3 /mnt/btrfs
  if [ $? -ne 0 ]; then
          dmesg | tail
          echo
          echo "Failed to mount in degraded mode"
          exit 1
  fi

  echo
  echo "File foo data (expected all bytes = 0xab):"
  od -A d -t x1 /mnt/btrfs/foo

  umount /mnt/btrfs

When running the reproducer:

  $ ./replace-test.sh
  wrote 10485760/10485760 bytes at offset 0
  10 MiB, 2560 ops; 0.0901 sec (110.877 MiB/sec and 28384.5216 ops/sec)
  Starting to replace /dev/sdg with /dev/sdi

  Running fstrim

  Unmounting filesystem
  Mounting filesystem in degraded mode using /dev/sdi only
  mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/sdi, missing codepage or helper program, or other error.
  [19581.748641] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi started
  [19581.803842] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi finished
  [19582.208293] BTRFS info (device sdi): allowing degraded mounts
  [19582.208298] BTRFS info (device sdi): disk space caching is enabled
  [19582.208301] BTRFS info (device sdi): has skinny extents
  [19582.212853] BTRFS warning (device sdi): devid 2 uuid 1f731f47-e1bb-4f00-bfbb-9e5a0cb4ba9f is missing
  [19582.213904] btree_readpage_end_io_hook: 25839 callbacks suppressed
  [19582.213907] BTRFS error (device sdi): bad tree block start, want 30490624 have 0
  [19582.214780] BTRFS warning (device sdi): failed to read root (objectid=7): -5
  [19582.231576] BTRFS error (device sdi): open_ctree failed

  Failed to mount in degraded mode

So fix by setting all allocated ranges in the replace target device when
the replace operation is finishing, when we are holding the chunk mutex
and we can not race with new chunk allocations.

A test case for fstests follows soon.

Fixes: 1c11b63 ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The NoMMU kernel is broken for QEMU virt machine from Linux-5.9-rc6
because clint_time_val is used even before CLINT driver is probed
at following places:
1. rand_initialize() calls get_cycles() which in-turn uses
   clint_time_val
2. boot_init_stack_canary() calls get_cycles() which in-turn
   uses clint_time_val

The issue#1 (above) is fixed by providing custom random_get_entropy()
for RISC-V NoMMU kernel. For issue#2 (above), we remove dependency of
boot_init_stack_canary() on get_cycles() and this is aligned with the
boot_init_stack_canary() implementations of ARM, ARM64 and MIPS kernel.

Fixes: d5be89a ("RISC-V: Resurrect the MMIO timer implementation for M-mode systems")
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
In IRQ handler we have to clear bitmap before use. Currently
the GCC extension has been used for that. For sake of the consistency
switch to bitmap API. As expected bloat-o-meter shows no difference
in the object size.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20200930142013.59247-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
When driver has been converted to the bitmap API the non-bitmap functions
started behaving differently on 32-bit BE architectures since the bytes in
two consequent unsigned longs are in different order in comparison to byte
array. Hence if the chip had had more than 32 lines the memset() call over
it would have not set up upper lines correctly.
Although it's currently a theoretical case (no supported chips of this type
has 32+ lines), it's better to provide a clean code to avoid people thinking
this is okay and potentially producing not fully working things.

Fixes: 35d13d9 ("gpio: pca953x: convert to use bitmap API")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20200930142013.59247-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Since commit ea426c2 ("mm: memcg: prepare for byte-sized vmstat
items") the write side of slab counters accepts a value in bytes and
converts it to pages.  It happens in __mod_node_page_state().

However a non-SMP version of __mod_node_page_state() doesn't perform
this conversion.  It leads to incorrect (unrealistically high) slab
counters values.  Fix this by adding a similar conversion to the non-SMP
version of __mod_node_page_state().

Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-and-tested-by: Bastian Bittorf <bb@npl.de>
Fixes: ea426c2 ("mm: memcg: prepare for byte-sized vmstat items")
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pm-cpufreq:
  cpufreq: intel_pstate: Fix missing return statement
Commit f227e3e ("random32: update the net random state on interrupt
and activity") broke compilation and was temporarily fixed by Linus in
83bdc72 ("random32: remove net_rand_state from the latent entropy
gcc plugin") by entirely moving net_rand_state out of the things handled
by the latent_entropy GCC plugin.

From what I understand when reading the plugin code, using the
__latent_entropy attribute on a declaration was the wrong part and
simply keeping the __latent_entropy attribute on the variable definition
was the correct fix.

Fixes: 83bdc72 ("random32: remove net_rand_state from the latent entropy gcc plugin")
Acked-by: Willy Tarreau <w@1wt.eu>
Cc: Emese Revfy <re.emese@gmail.com>
Signed-off-by: Thibaut Sautereau <thibaut.sautereau@ssi.gouv.fr>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
…el/git/ulfh/mmc

Pull MMC fixes from Ulf Hansson:

 - Fix deadlock when removing MEMSTICK host

 - Workaround broken CMDQ on Intel GLK based IRBIS models

* tag 'mmc-v5.9-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: sdhci: Workaround broken command queuing on Intel GLK based IRBIS models
  memstick: Skip allocating card when removing host
…git/linusw/linux-gpio

Pull GPIO fixes from Linus Walleij:
 "Some late GPIO fixes for the v5.9 series:

   - Fix compiler warnings on the OMAP when PM is disabled

   - Clear the interrupt when setting edge sensitivity on the Spreadtrum
     driver.

   - Fix up spurious interrupts on the TC35894.

   - Support threaded interrupts on the Siox controller.

   - Fix resource leaks on the mockup driver.

   - Fix line event handling in syscall compatible mode for the
     character device.

   - Fix an unitialized variable in the PCA953A driver.

   - Fix access to all GPIO IRQs on the Aspeed AST2600.

   - Fix line direction on the AMD FCH driver.

   - Use the bitmap API instead of compiler intrinsics for bit
     manipulation in the PCA953x driver"

* tag 'gpio-v5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: pca953x: Correctly initialize registers 6 and 7 for PCA957x
  gpio: pca953x: Use bitmap API over implicit GCC extension
  gpio: amd-fch: correct logic of GPIO_LINE_DIRECTION
  gpio: aspeed: fix ast2600 bank properties
  gpio/aspeed-sgpio: don't enable all interrupts by default
  gpio/aspeed-sgpio: enable access to all 80 input & output sgpios
  gpio: pca953x: Fix uninitialized pending variable
  gpiolib: Fix line event handling in syscall compatible mode
  gpio: mockup: fix resource leak in error path
  gpio: siox: explicitly support only threaded irqs
  gpio: tc35894: fix up tc35894 interrupt configuration
  gpio: sprd: Clear interrupt when setting the type as edge
  gpio: omap: Fix warnings if PM is disabled
…nel/git/gregkh/staging

Pull IIO fixes from Greg KH:
 "Here are two small IIO driver fixes for 5.9-rc8 that resolve some
  reported issues:

   - driver name fixed in one driver

   - device name typo fixed

  Both have been in linux-next for a while with no reported problems"

* tag 'staging-5.9-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  iio: adc: qcom-spmi-adc5: fix driver name
  iio: adc: ad7124: Fix typo in device name
…it/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix one more issue related to the recent RCU-lockdep changes, a
  typo in documentation and add a missing return statement to
  intel_pstate.

  Specifics:

   - Fix up RCU usage for cpuidle on the ARM imx6q platform (Ulf
     Hansson)

   - Fix typo in the PM documentation (Yoann Congal)

   - Add return statement that is missing after recent changes in the
     intel_pstate driver (Zhang Rui)"

* tag 'pm-5.9-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ARM: imx6q: Fixup RCU usage for cpuidle
  Documentation: PM: Fix a reStructuredText syntax error
  cpufreq: intel_pstate: Fix missing return statement
…nel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two more fixes.

  One is for a lockdep warning/lockup (also caught by syzbot), that one
  has been seen in practice. Regarding the other syzbot reports
  mentioned last time, they don't seem to be urgent and reliably
  reproducible so they'll be fixed later.

  The second fix is for a potential corruption when device replace
  finishes and the in-memory state of trim is not copied to the new
  device"

* tag 'for-5.9-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix filesystem corruption after a device replace
  btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks
  btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing
…inux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:
 "Two fixes for this week:

   - The addition of a symbol export for clint_time_val, which has been
     inlined into some timex functions and can be used by drivers.

   - A fix to avoid calling get_cycles() before the timers have been
     probed.

  These both only effect !MMU systems"

* tag 'riscv-for-linus-5.9-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Check clint_time_val before use
  clocksource: clint: Export clint_time_val for modules
…l/git/viro/vfs

Pull epoll fixes from Al Viro:
 "Several race fixes in epoll"

* 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ep_create_wakeup_source(): dentry name can change under you...
  epoll: EPOLL_CTL_ADD: close the race in decision to take fast path
  epoll: replace ->visited/visited_list with generation count
  epoll: do not insert into poll queues until all sanity checks are done
@pull pull bot added the ⤵️ pull label Oct 2, 2020
@pull pull bot merged commit d4fce2e into vchong:master Oct 2, 2020
pull bot pushed a commit that referenced this pull request Oct 8, 2022
This patch fix the follwing checkpatch warnings:

	WARNING: quoted string split across lines
	#129: FILE: drivers/staging/vme_user/vme_tsi148.c:129:
	+			dev_err(tsi148_bridge->parent, "VME Mailbox %d received"
	+				": 0x%x\n", i, val);

	WARNING: quoted string split across lines
	#147: FILE: drivers/staging/vme_user/vme_tsi148.c:147:
	+	dev_err(tsi148_bridge->parent, "PCI Exception at address: 0x%08x:%08x, "
	+		"attributes: %08x\n",

	WARNING: quoted string split across lines
	#153: FILE: drivers/staging/vme_user/vme_tsi148.c:153:
	+	dev_err(tsi148_bridge->parent, "PCI-X attribute reg: %08x, PCI-X split "
	+		"completion reg: %08x\n",

	WARNING: quoted string split across lines
	#185: FILE: drivers/staging/vme_user/vme_tsi148.c:185:
	+		dev_err(tsi148_bridge->parent, "VME Bus Exception Overflow "
	+			"Occurred\n");

	WARNING: quoted string split across lines
	#321: FILE: drivers/staging/vme_user/vme_tsi148.c:321:
	+		dev_err(tsi148_bridge->parent, "Can't get assigned pci irq "
	+			"vector %02X\n", pdev->irq);

	WARNING: quoted string split across lines
	#533: FILE: drivers/staging/vme_user/vme_tsi148.c:533:
	+		dev_err(tsi148_bridge->parent, "Invalid PCI Offset "
	+			"alignment\n");

	WARNING: space prohibited before semicolon
	#591: FILE: drivers/staging/vme_user/vme_tsi148.c:591:
	+		temp_ctl |= TSI148_LCSR_ITAT_SUPR ;

	WARNING: quoted string split across lines
	#766: FILE: drivers/staging/vme_user/vme_tsi148.c:766:
	+		dev_err(tsi148_bridge->parent, "Failed to allocate mem "
	+			"resource for window %d size 0x%lx start 0x%lx\n",

	WARNING: quoted string split across lines
	#831: FILE: drivers/staging/vme_user/vme_tsi148.c:831:
	+		dev_err(tsi148_bridge->parent, "Invalid VME Window "
	+			"alignment\n");
	WARNING: quoted string split across lines
	#838: FILE: drivers/staging/vme_user/vme_tsi148.c:838:
	+		dev_err(tsi148_bridge->parent, "Size must be non-zero for "
	+			"enabled windows\n");

	WARNING: quoted string split across lines
	#853: FILE: drivers/staging/vme_user/vme_tsi148.c:853:
	+		dev_err(tsi148_bridge->parent, "Unable to allocate memory for "
	+			"resource\n");

	WARNING: quoted string split across lines
	#894: FILE: drivers/staging/vme_user/vme_tsi148.c:894:
	+		dev_err(tsi148_bridge->parent, "Invalid VME Offset "
	+			"alignment\n");

	WARNING: quoted string split across lines
	#941: FILE: drivers/staging/vme_user/vme_tsi148.c:941:
	+		dev_warn(tsi148_bridge->parent, "Currently not setting "
	+			"Broadcast Select Registers\n");

	WARNING: quoted string split across lines
	#1455: FILE: drivers/staging/vme_user/vme_tsi148.c:1455:
	+		dev_err(dev, "Currently not setting Broadcast Select "
	+			"Registers\n");

	WARNING: quoted string split across lines
	#1554: FILE: drivers/staging/vme_user/vme_tsi148.c:1554:
	+		dev_err(dev, "Currently not setting Broadcast Select "
	+			"Registers\n");

	WARNING: quoted string split across lines
	#1643: FILE: drivers/staging/vme_user/vme_tsi148.c:1643:
	+		dev_err(tsi148_bridge->parent, "Descriptor not aligned to 8 "
	+			"byte boundary as required: %p\n",

	WARNING: else is not generally useful after a break or return
	#1830: FILE: drivers/staging/vme_user/vme_tsi148.c:1830:
	+		return -EBUSY;
	+	} else {

	warning: quoted string split across lines
	#1939: file: drivers/staging/vme_user/vme_tsi148.c:1939:
	+			dev_err(tsi148_bridge->parent, "location monitor "
	+				"callback attached, can't reset\n");

	WARNING: space prohibited before semicolon
	#1964: FILE: drivers/staging/vme_user/vme_tsi148.c:1964:
	+		lm_ctl |= TSI148_LCSR_LMAT_SUPR ;

	WARNING: quoted string split across lines
	#2055: FILE: drivers/staging/vme_user/vme_tsi148.c:2055:
	+		dev_err(tsi148_bridge->parent, "Location monitor not properly "
	+			"configured\n");

	WARNING: quoted string split across lines
	#2200: FILE: drivers/staging/vme_user/vme_tsi148.c:2200:
	+		dev_err(tsi148_bridge->parent, "Failed to allocate memory for "
	+			"CR/CSR image\n");

	WARNING: quoted string split across lines
	#2241: FILE: drivers/staging/vme_user/vme_tsi148.c:2241:
	+			dev_err(tsi148_bridge->parent, "Configuring flush image"
	+				" failed\n");

Signed-off-by: Mingyi Kang <jerrykang026@gmail.com>
Link: https://lore.kernel.org/r/20220730045726.55452-1-jerrykang026@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull bot pushed a commit that referenced this pull request Mar 22, 2024
…find_and_get_node_by_id()

The BPF helper bpf_cgroup_from_id() calls kernfs_find_and_get_node_by_id()
which acquires kernfs_idr_lock, which is an non-raw non-IRQ-safe lock. This
can lead to deadlocks as bpf_cgroup_from_id() can be called from any BPF
programs including e.g. the ones that attach to functions which are holding
the scheduler rq lock.

Consider the following BPF program:

  SEC("fentry/__set_cpus_allowed_ptr_locked")
  int BPF_PROG(__set_cpus_allowed_ptr_locked, struct task_struct *p,
	       struct affinity_context *affn_ctx, struct rq *rq, struct rq_flags *rf)
  {
	  struct cgroup *cgrp = bpf_cgroup_from_id(p->cgroups->dfl_cgrp->kn->id);

	  if (cgrp) {
		  bpf_printk("%d[%s] in %s", p->pid, p->comm, cgrp->kn->name);
		  bpf_cgroup_release(cgrp);
	  }
	  return 0;
  }

__set_cpus_allowed_ptr_locked() is called with rq lock held and the above
BPF program calls bpf_cgroup_from_id() within leading to the following
lockdep warning:

  =====================================================
  WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
  6.7.0-rc3-work-00053-g07124366a1d7-dirty #147 Not tainted
  -----------------------------------------------------
  repro/1620 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
  ffffffff833b3688 (kernfs_idr_lock){+.+.}-{2:2}, at: kernfs_find_and_get_node_by_id+0x1e/0x70

		and this task is already holding:
  ffff888237ced698 (&rq->__lock){-.-.}-{2:2}, at: task_rq_lock+0x4e/0xf0
  which would create a new lock dependency:
   (&rq->__lock){-.-.}-{2:2} -> (kernfs_idr_lock){+.+.}-{2:2}
  ...
   Possible interrupt unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(kernfs_idr_lock);
				 local_irq_disable();
				 lock(&rq->__lock);
				 lock(kernfs_idr_lock);
    <Interrupt>
      lock(&rq->__lock);

		 *** DEADLOCK ***
  ...
  Call Trace:
   dump_stack_lvl+0x55/0x70
   dump_stack+0x10/0x20
   __lock_acquire+0x781/0x2a40
   lock_acquire+0xbf/0x1f0
   _raw_spin_lock+0x2f/0x40
   kernfs_find_and_get_node_by_id+0x1e/0x70
   cgroup_get_from_id+0x21/0x240
   bpf_cgroup_from_id+0xe/0x20
   bpf_prog_98652316e9337a5a___set_cpus_allowed_ptr_locked+0x96/0x11a
   bpf_trampoline_6442545632+0x4f/0x1000
   __set_cpus_allowed_ptr_locked+0x5/0x5a0
   sched_setaffinity+0x1b3/0x290
   __x64_sys_sched_setaffinity+0x4f/0x60
   do_syscall_64+0x40/0xe0
   entry_SYSCALL_64_after_hwframe+0x46/0x4e

Let's fix it by protecting kernfs_node and kernfs_root with RCU and making
kernfs_find_and_get_node_by_id() acquire rcu_read_lock() instead of
kernfs_idr_lock.

This adds an rcu_head to kernfs_node making it larger by 16 bytes on 64bit.
Combined with the preceding rearrange patch, the net increase is 8 bytes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrea Righi <andrea.righi@canonical.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20240109214828.252092-4-tj@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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