From: Peter Zijlstra <pet...@infradead.org> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== 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.wea...@maine.edu> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmy...@git.kernel.org Signed-off-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Jiri Slaby <jsl...@suse.cz> --- kernel/events/core.c | 3 +++ 1 file changed, 3 insertions(+) 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; } /* -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
