Ravi Bangoria <ravi.bango...@linux.ibm.com> writes:
> Peter / mpe,
>
> Is the v2 looks good? If so, can anyone of you please pick this up.
I usually wouldn't take it, it's generic perf code. Unless
peter/ingo/acme tell me otherwise.
It's sort of a bug fix for 0819b2e30ccb, should it have a fixes and/or
stable tag?
Fixes: 0819b2e30ccb ("perf: Limit perf_event_attr::sample_period to 63 bits")
Cc: sta...@vger.kernel.org # v3.15+
cheers
> On 6/4/19 9:59 AM, Ravi Bangoria wrote:
>> 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.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;
>> +
>> event_function_call(event, __perf_event_period, &value);
>>
>> return 0;
>>
