Commit 0050c7b2 authored Jan 03, 2020 by Paul E. McKenney

locking/rtmutex: rcu: Add WRITE_ONCE() to rt_mutex ->owner



The rt_mutex structure's ->owner field is read locklessly, so this
commit adds the WRITE_ONCE() to an update in order to provide proper
documentation and READ_ONCE()/WRITE_ONCE() pairing.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>

parent 105abf82

kernel/locking/rtmutex.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -57,7 +57,7 @@ rt_mutex_set_owner(struct rt_mutex lock, struct task_struct owner)
		if (rt_mutex_has_waiters(lock))
		val \|= RT_MUTEX_HAS_WAITERS;

		lock->owner = (struct task_struct *)val;
		WRITE_ONCE(lock->owner, (struct task_struct *)val);
		}

		static inline void clear_rt_mutex_waiters(struct rt_mutex *lock)

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