Add defensive checks to halide_buffer_copy_already_locked #6401
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Found while debugging crashes with performance_async_gpu for OpenGLCompute: the 'if' tree wasn't robust enough for malformed buffers being passed, and could attempt to deref and use a null src->device_interface or dst->device_interface in some cases. This patch just improves this function to return an error in these cases (rather than crashing); the fact that we are getting malformed buffers passed to us is likely a separate bug.
abadams
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Nov 9, 2021
shoaibkamil
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Nov 9, 2021
steven-johnson
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Nov 9, 2021
We currently assume that _halide_buffer_crop() will never fail. This is a bad assumption, as it can call device_crop(), which can fail due to unexpected runtime errors, or from a backend simply leaving the `device_crop` field at the default (unimplemented) case (as is currently the case for the OGLC backend). When this happens, the `dst` buffer was left in an inconsistent, invalid state (which was what led to the crashes fixed by #6401). This change modifies _halide_buffer_crop() to return nullptr in the event of an error, and to wrap all callers in a `require()` clause to check the result. (This is not optimal, of course, since the specific error returned by device_crop is getting dropped on the floor, but the existence of an error is no longer ignored.) This addresses at least some of the failure issues we are seeing in performance_async_gpu with the OpenGLCompute backend. (Also: drive-by whitespace fix in CodegenC)
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Failure is unrelated. |
steven-johnson
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(Alternate to #6402) We currently assume that _halide_buffer_crop() will never fail. This is a bad assumption, as it can call device_crop(), which can fail due to unexpected runtime errors, or from a backend simply leaving the device_crop field at the default (unimplemented) case (as is currently the case for the OGLC backend). When this happens, the dst buffer was left in an inconsistent, invalid state (which was what led to the crashes fixed by #6401). This change modifies _halide_buffer_crop() to return nullptr in the event of an error, and ensure that all cropped buffers are checked for null at the right point. (This is not optimal, of course, since the specific error returned by device_crop is getting dropped on the floor, but the existence of an error is no longer ignored.) This addresses at least some of the failure issues we are seeing in performance_async_gpu with the OpenGLCompute backend. (Also: drive-by whitespace fix in CodegenC)
steven-johnson
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Nov 11, 2021
* _halide_buffer_crop() needs to check for runtime failures (v2) (Alternate to #6402) We currently assume that _halide_buffer_crop() will never fail. This is a bad assumption, as it can call device_crop(), which can fail due to unexpected runtime errors, or from a backend simply leaving the device_crop field at the default (unimplemented) case (as is currently the case for the OGLC backend). When this happens, the dst buffer was left in an inconsistent, invalid state (which was what led to the crashes fixed by #6401). This change modifies _halide_buffer_crop() to return nullptr in the event of an error, and ensure that all cropped buffers are checked for null at the right point. (This is not optimal, of course, since the specific error returned by device_crop is getting dropped on the floor, but the existence of an error is no longer ignored.) This addresses at least some of the failure issues we are seeing in performance_async_gpu with the OpenGLCompute backend. (Also: drive-by whitespace fix in CodegenC) * Oops
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Found while debugging crashes with performance_async_gpu for OpenGLCompute: the 'if' tree wasn't robust enough for malformed buffers being passed, and could attempt to deref and use a null src->device_interface or dst->device_interface in some cases.
This patch just improves this function to return an error in these cases (rather than crashing); the fact that we are getting malformed buffers passed to us is likely a separate bug.