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Subject[PATCH v2] perf ioctl: Add check for the sample_period value
Date
perf_event_open() limits the sample_period to 63 bits. See
commit 0819b2e30ccb ("perf: Limit perf_event_attr::sample_period
to 63 bits"). Make ioctl() consistent with it.

Also on powerpc, negative sample_period could cause a recursive
PMIs leading to a hang (reported when running perf-fuzzer).

Signed-off-by: Ravi Bangoria <ravi.bangoria@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;
+
event_function_call(event, __perf_event_period, &value);

return 0;
--
2.20.1
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