Commit febd668d authored May 18, 2020 by Paolo Bonzini

rcuwait: avoid lockdep splats from rcuwait_active()



rcuwait_active only returns whether w->task is not NULL.  This is
exactly one of the usecases that are mentioned in the documentation
for rcu_access_pointer() where it is correct to bypass lockdep checks.

This avoids a splat from kvm_vcpu_on_spin().

Reported-by: Wanpeng Li <kernellwp@gmail.com>
Tested-by: Wanpeng Li <kernellwp@gmail.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent cb953129

include/linux/rcuwait.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -31,7 +31,7 @@ static inline void rcuwait_init(struct rcuwait *w)
		*/
		static inline int rcuwait_active(struct rcuwait *w)
		{
		return !!rcu_dereference(w->task);
		return !!rcu_access_pointer(w->task);
		}

		extern int rcuwait_wake_up(struct rcuwait *w);

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