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Message-Id: <6486385d1f30336e9973b24c8c65f5079543d3d3.1537377064.git.reinette.chatre@intel.com>
Date: Wed, 19 Sep 2018 10:29:06 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: tglx@...utronix.de, fenghua.yu@...el.com, tony.luck@...el.com,
peterz@...radead.org, mingo@...hat.com, acme@...nel.org
Cc: gavin.hindman@...el.com, jithu.joseph@...el.com,
dave.hansen@...el.com, hpa@...or.com, x86@...nel.org,
linux-kernel@...r.kernel.org,
Reinette Chatre <reinette.chatre@...el.com>
Subject: [PATCH V5 1/6] perf/core: Add sanity check to deal with pinned event failure
It is possible that a failure can occur during the scheduling of a
pinned event. The initial portion of perf_event_read_local() contains
the various error checks an event should pass before it can be
considered valid. Ensure that the potential scheduling failure
of a pinned event is checked for and have a credible error.
Link: http://lkml.kernel.org/r/20180807093615.GY2494@hirez.programming.kicks-ass.net
Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>
---
kernel/events/core.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2a62b96600ad..191c0c2e10de 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3940,6 +3940,12 @@ int perf_event_read_local(struct perf_event *event, u64 *value,
goto out;
}
+ /* If this is a pinned event it must be running on this CPU */
+ if (event->attr.pinned && event->oncpu != smp_processor_id()) {
+ ret = -EBUSY;
+ goto out;
+ }
+
/*
* If the event is currently on this CPU, its either a per-task event,
* or local to this CPU. Furthermore it means its ACTIVE (otherwise
--
2.17.0
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