locking/mutex: Add MUTEX_WARN_ON() into fast path

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Scenario: In platform_device_register, the driver misuses struct
device as platform_data, making kmemdup duplicate a device. Accessing
the duplicate may cause list corruption due to its mutex magic or list
holding old content.
It recurs randomly as the first mutex - getting process skips the slow
path and mutex check. Adding MUTEX_WARN_ON(lock->magic!= lock) in
__mutex_trylock_fast() makes it always happen.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250126033243.53069-1-cuiyunhui@bytedance.com

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Yunhui Cui 2025-01-26 11:32:43 +08:00 • committed by Peter Zijlstra

parent 2d352ec9fc

commit 337369f8ce

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kernel/locking/mutex.c

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