From: Nitesh Konkar <niteshkonkar.libvirt@gmail.com>
Date: Tue, 24 Jan 2017 09:12:03 +0000 (+0530)
Subject: perf: Prevent enabling of already enabled perf event
X-Git-Tag: CVE-2017-2635~232
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=26ac16f3ce68961a2b90469b284ad6c07bdd6320;p=thirdparty%2Flibvirt.git

perf: Prevent enabling of already enabled perf event

Currently, on every --enable perf_event command,
a new event->fd is created and counting of perf
event counter starts from zero and previous
event->fd is lost. This patch prevents this
behaviour.

Signed-off-by: Nitesh Konkar <nitkon12@linux.vnet.ibm.com>
---

diff --git a/src/util/virperf.c b/src/util/virperf.c
index f64692bf39..4493608a0f 100644
--- a/src/util/virperf.c
+++ b/src/util/virperf.c
@@ -198,6 +198,9 @@ virPerfEventEnable(virPerfPtr perf,
     if (!event || !event_attr)
         return -1;
 
+    if (event->enabled)
+        return 0;
+
     if (event_attr->attrType == 0 && (type == VIR_PERF_EVENT_CMT ||
                                        type == VIR_PERF_EVENT_MBMT ||
                                        type == VIR_PERF_EVENT_MBML)) {