From febd668d375caf13a7fcd93b3498366854de854a Mon Sep 17 00:00:00 2001 From: Paolo Bonzini <pbonzini@redhat.com> Date: Mon, 18 May 2020 06:30:09 -0400 Subject: [PATCH] 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> --- include/linux/rcuwait.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h index c1414ce44abc..61c56cca95c4 100644 --- a/include/linux/rcuwait.h +++ b/include/linux/rcuwait.h @@ -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); -- 2.30.9