From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 19 Nov 2019 12:14:29 +0000 (+0100)
Subject: perf/core: Add SRCU annotation for pmus list walk
X-Git-Tag: microblaze-v5.7-rc1~374^2
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=9f0bff1180efc9ea988fed3fd93da7647151ac8b;p=linux-2.6-microblaze.git

perf/core: Add SRCU annotation for pmus list walk

Since commit
   28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")

there is an additional check to ensure that a RCU related lock is held
while the RCU list is iterated.
This section holds the SRCU reader lock instead.

Add annotation to list_for_each_entry_rcu() that pmus_srcu must be
acquired during the list traversal.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Link: https://lkml.kernel.org/r/20191119121429.zhcubzdhm672zasg@linutronix.de
---

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4ff86d57f9e5..a1f8bde19b56 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10523,7 +10523,7 @@ again:
 		goto unlock;
 	}
 
-	list_for_each_entry_rcu(pmu, &pmus, entry) {
+	list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
 		ret = perf_try_init_event(pmu, event);
 		if (!ret)
 			goto unlock;