On Sat, May 11, 2019 at 08:12:16AM +0530, Ravi Bangoria wrote: > Add a check for sample_period value sent from userspace. Negative > value does not make sense. And in powerpc arch code this could cause > a recursive PMI leading to a hang (reported when running perf-fuzzer). > > Signed-off-by: Ravi Bangoria <ravi.bango...@linux.ibm.com> > --- > kernel/events/core.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index abbd4b3b96c2..e44c90378940 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -5005,6 +5005,9 @@ static int perf_event_period(struct perf_event *event, > u64 __user *arg) > if (perf_event_check_period(event, value)) > return -EINVAL; > > + if (!event->attr.freq && (value & (1ULL << 63))) > + return -EINVAL;
Well, perf_event_attr::sample_period is __u64. Would not be the site using it as signed be the one in error?
