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perf/core: Check return value of the perf_event_read() IPI

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The call to smp_call_function_single in perf_event_read() may fail if
an invalid or not online CPU index is passed. Warn user if such bug is
present and return error.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1471467307-61171-2-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
David Carrillo-Cisneros 2016-08-17 13:55:04 -07:00 committed by Ingo Molnar
parent 99f5bc9bfa
commit 71e7bc2bab
1 changed files with 4 additions and 3 deletions
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7
kernel/events/core.c
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@ -3549,9 +3549,10 @@ static int perf_event_read(struct perf_event *event, bool group)
.group = group, .group = group,
.ret = 0, .ret = 0,
}; };
smp_call_function_single(event->oncpu, ret = smp_call_function_single(event->oncpu, __perf_event_read, &data, 1);
__perf_event_read, &data, 1); /* The event must have been read from an online CPU: */
ret = data.ret; WARN_ON_ONCE(ret);
ret = ret ? : data.ret;
} else if (event->state == PERF_EVENT_STATE_INACTIVE) { } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
struct perf_event_context *ctx = event->ctx; struct perf_event_context *ctx = event->ctx;
unsigned long flags; unsigned long flags;