From: Peter Zijlstra Date: Thu, 15 May 2014 18:23:48 +0000 (+0200) Subject: perf: Limit perf_event_attr::sample_period to 63 bits X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=0819b2e30ccb93edf04876237b6205eef84ec8d2;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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: Vince Weaver Signed-off-by: Peter Zijlstra Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.org Signed-off-by: Thomas Gleixner --- diff --git a/kernel/events/core.c b/kernel/events/core.c index 71232844f235..1d1ec6453a08 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7029,6 +7029,9 @@ 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; } /*