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| author | Peter Zijlstra <peterz@infradead.org> | 2014-05-15 20:23:48 +0200 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-06-20 17:33:52 +0200 |
| commit | ed8acba3f62f4cb479628215582b487872c398d7 (patch) | |
| tree | 68f5ce0a88df09a943baf0ae08bcf2e9b35afc57 /kernel | |
| parent | e36e8c8f72bc4f8309bf0dea92d58aa661c74c84 (diff) | |
| download | lwn-ed8acba3f62f4cb479628215582b487872c398d7.tar.gz lwn-ed8acba3f62f4cb479628215582b487872c398d7.zip | |
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: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 6e0f9648fa68..01eeaf6cc95a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6956,6 +6956,9 @@ 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; } /* |