locking/mutex: Add MUTEX_WARN_ON() into fast path

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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: cuiyunhui

kernel/locking/mutex.c

@@ -143,6 +143,8 @@ static __always_inline bool __mutex_trylock_fast(struct mutex *lock)
 	unsigned long curr = (unsigned long)current;
 	unsigned long zero = 0UL;
 
+	MUTEX_WARN_ON(lock->magic != lock);
+
 	if (atomic_long_try_cmpxchg_acquire(&lock->owner, &zero, curr))
 		return true;