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authorPeter Zijlstra <peterz@infradead.org>2015-09-10 11:58:27 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-22 14:49:14 -0700
commitd78a2be4f9a1b9a31dff96e17d175860c30db4c2 (patch)
treeb9e88771762a43eb2795a110aa334a25c7c3006a
parent23f8f4326a15a7f04656f19fa94aa385eef67e4d (diff)
downloadlwn-d78a2be4f9a1b9a31dff96e17d175860c30db4c2.tar.gz
lwn-d78a2be4f9a1b9a31dff96e17d175860c30db4c2.zip
perf/x86/intel: Fix constraint access
commit ebfb4988f0378e2ac3b4a0aa1ea20d724293f392 upstream. Sasha reported that we can get here with .idx==-1, and cpuc->event_constraints unallocated. Suggested-by: Stephane Eranian <eranian@google.com> Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: b371b5943178 ("perf/x86: Fix event/group validation") Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 6326ae24e4d5..1b09c420c7ff 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2102,9 +2102,12 @@ static struct event_constraint *
intel_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
struct perf_event *event)
{
- struct event_constraint *c1 = cpuc->event_constraint[idx];
+ struct event_constraint *c1 = NULL;
struct event_constraint *c2;
+ if (idx >= 0) /* fake does < 0 */
+ c1 = cpuc->event_constraint[idx];
+
/*
* first time only
* - static constraint: no change across incremental scheduling calls