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authorAndy Lutomirski <luto@kernel.org>2017-03-16 20:59:39 +0100
committerIngo Molnar <mingo@kernel.org>2017-03-17 08:28:26 +0100
commit5dc855d44c2ad960a86f593c60461f1ae1566b6d (patch)
tree2c4b0b1b3f07901812f2b8459000c161e735936a /arch
parentperf/core: Better explain the inherit magic (diff)
downloadlinux-5dc855d44c2ad960a86f593c60461f1ae1566b6d.tar.xz
linux-5dc855d44c2ad960a86f593c60461f1ae1566b6d.zip
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: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Andy 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: 7911d3f7af14 ("perf/x86: Only allow rdpmc if a perf_event is mapped") Link: http://lkml.kernel.org/r/0c5b38a76ea50e405f9abe07a13dfaef87c173a1.1489694270.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/events/core.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 1635c0c8df23..e07b36c5588a 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -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)