Patch "perf/x86/intel: Fix constraint access" has been added to the 4.2-stable tree

Patch "perf/x86/intel: Fix constraint access" has been added to the 4.2-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    perf/x86/intel: Fix constraint access

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-x86-intel-fix-constraint-access.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ebfb4988f0378e2ac3b4a0aa1ea20d724293f392 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Thu, 10 Sep 2015 11:58:27 +0200
Subject: perf/x86/intel: Fix constraint access

From: Peter Zijlstra <peterz@infradead.org>

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>

---
 arch/x86/kernel/cpu/perf_event_intel.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- 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


Patches currently in stable-queue which might be from peterz@infradead.org are

queue-4.2/time-fix-timekeeping_freqadjust-s-incorrect-use-of-abs-instead-of-abs64.patch
queue-4.2/perf-x86-intel-fix-constraint-access.patch
queue-4.2/sched-access-local-runqueue-directly-in-single_task_running.patch
queue-4.2/locking-qspinlock-x86-only-emit-the-test-and-set-fallback-when-building-guest-support.patch
queue-4.2/locking-qspinlock-x86-fix-performance-regression-under-unaccelerated-vms.patch