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 4ff86d57f9e5309905e7e5cffe5a1eb875b45e30..a1f8bde19b561a03ff09cd817d4013512d7f5383 100644 (file)
--- 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;