KCSAN reports:
BUG: KCSAN: data-race in do_raw_write_lock / do_raw_write_lock
write (marked) to 0xffff800009cf504c of 4 bytes by task 1102 on cpu 1:
do_raw_write_lock+0x120/0x204
_raw_write_lock_irq
do_exit
call_usermodehelper_exec_async
ret_from_fork
read to 0xffff800009cf504c of 4 bytes by task 1103 on cpu 0:
do_raw_write_lock+0x88/0x204
_raw_write_lock_irq
do_exit
call_usermodehelper_exec_async
ret_from_fork
value changed: 0xffffffff -> 0x00000001
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1103 Comm: kworker/u4:1 6.1.111
Commit 1a365e8223 ("locking/spinlock/debug: Fix various data races") has
adressed most of these races, but seems to be not consistent/not complete.
>From do_raw_write_lock() only debug_write_lock_after() part has been
converted to WRITE_ONCE(), but not debug_write_lock_before() part.
Do it now.
Fixes: 1a365e8223 ("locking/spinlock/debug: Fix various data races")
Reported-by: Adrian Freihofer <adrian.freihofer@siemens.com>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: stable@vger.kernel.org
c14ecb555c