Commit 5dc855d4 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar

x86/perf: Fix CR4.PCE propagation to use active_mm instead of mm

If one thread mmaps a perf event while another thread in the same mm
is in some context where active_mm != mm (which can happen in the
scheduler, for example), refresh_pce() would write the wrong value
to CR4.PCE.  This broke some PAPI tests.
Reported-and-tested-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 7911d3f7 ("perf/x86: Only allow rdpmc if a perf_event is mapped")
Link: http://lkml.kernel.org/r/0c5b38a76ea50e405f9abe07a13dfaef87c173a1.1489694270.git.luto@kernel.orgSigned-off-by: Ingo Molnar's avatarIngo Molnar <mingo@kernel.org>
parent d8a8cfc7
......@@ -2100,8 +2100,8 @@ static int x86_pmu_event_init(struct perf_event *event)
static void refresh_pce(void *ignored)
{
if (current->mm)
load_mm_cr4(current->mm);
if (current->active_mm)
load_mm_cr4(current->active_mm);
}
static void x86_pmu_event_mapped(struct perf_event *event)
......
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