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Commit c96ea7cf authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Paul E. McKenney
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rcu: Avoid spurious RCU CPU stall warnings 



If a given CPU avoids the idle loop but also avoids starting a new
RCU grace period for a full minute, RCU can issue spurious RCU CPU
stall warnings.  This commit fixes this issue by adding a check for
ongoing grace period to avoid these spurious stall warnings.

Reported-by: default avatarBecky Bruce <bgillbruce@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent c8020a67

kernel/rcutree.c

+2 −1
Original line number Diff line number Diff line
@@ -819,7 +819,8 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) 
	j = ACCESS_ONCE(jiffies);

	js = ACCESS_ONCE(rsp->jiffies_stall);

	rnp = rdp->mynode;

	if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {

	if (rcu_gp_in_progress(rsp) &&

	    (ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {



		/* We haven't checked in, so go dump stack. */

		print_cpu_stall(rsp);