Commit 0819b2e3 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner

perf: Limit perf_event_attr::sample_period to 63 bits

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: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.orgSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent a45e9038
...@@ -7029,6 +7029,9 @@ SYSCALL_DEFINE5(perf_event_open, ...@@ -7029,6 +7029,9 @@ SYSCALL_DEFINE5(perf_event_open,
if (attr.freq) { if (attr.freq) {
if (attr.sample_freq > sysctl_perf_event_sample_rate) if (attr.sample_freq > sysctl_perf_event_sample_rate)
return -EINVAL; return -EINVAL;
} else {
if (attr.sample_period & (1ULL << 63))
return -EINVAL;
} }
/* /*
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment