Messages in this thread |  | | Date | Mon, 7 Aug 2017 07:09:39 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] rcu: Fix up pending cbs check in rcu_prepare_for_idle |
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On Mon, Aug 07, 2017 at 07:31:27PM +0530, Neeraj Upadhyay wrote: > > > On 08/07/2017 06:10 PM, Paul E. McKenney wrote: > >On Mon, Aug 07, 2017 at 11:20:10AM +0530, Neeraj Upadhyay wrote: > >>Pending cbs check in rcu_prepare_for_idle is inversed > >>in the sense that, it should accelerate if there are > >>pending cbs; but, the check does the opposite. So, > >>fix it. > >> > >>Fixes: 15fecf89e46a ("srcu: Abstract multi-tail callback list handling") > >>Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> > >Good catch! Queued for review and testing. > > > >Just out of curiosity, how did you find this one? > > Hi Paul, found the issue while reading the code.
Very good, and please feel free to continue reading and finding more bugs! ;-)
Thanx, Paul
> >>--- > >> kernel/rcu/tree_plugin.h | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >>diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > >>index 908b309..b8f51df 100644 > >>--- a/kernel/rcu/tree_plugin.h > >>+++ b/kernel/rcu/tree_plugin.h > >>@@ -1493,7 +1493,7 @@ static void rcu_prepare_for_idle(void) > >> rdtp->last_accelerate = jiffies; > >> for_each_rcu_flavor(rsp) { > >> rdp = this_cpu_ptr(rsp->rda); > >>- if (rcu_segcblist_pend_cbs(&rdp->cblist)) > >>+ if (!rcu_segcblist_pend_cbs(&rdp->cblist)) > >> continue; > >> rnp = rdp->mynode; > >> raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ > >>-- > >>QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a > >>member of the Code Aurora Forum, hosted by The Linux Foundation > >> > > -- > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a > member of the Code Aurora Forum, hosted by The Linux Foundation >
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