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authorPeter Zijlstra <peterz@infradead.org>2014-05-15 20:23:48 +0200
committerShow Liu <show.liu@linaro.org>2014-06-18 12:05:17 +0800
commit80e48078a05d99c80051efb7509f87ae95d08914 (patch)
treedd725ec2c727000c189a8362b577c1bf6ffca4bf
parentcfb8ee015ee76965974e8270dba24dd2b5f3349f (diff)
perf: Limit perf_event_attr::sample_period to 63 bits
commit 0819b2e30ccb93edf04876237b6205eef84ec8d2 upstream. Vince reported that using a large sample_period (one with bit 63 set) results in wreckage since while the sample_period is fundamentally unsigned (negative periods don't make sense) the way we implement things very much rely on signed logic. So limit sample_period to 63 bits to avoid tripping over this. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/events/core.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index e80611f1f8a..e7561718687 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7025,6 +7025,9 @@ SYSCALL_DEFINE5(perf_event_open,
if (attr.freq) {
if (attr.sample_freq > sysctl_perf_event_sample_rate)
return -EINVAL;
+ } else {
+ if (attr.sample_period & (1ULL << 63))
+ return -EINVAL;
}
/*