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s390/cpum_sf: ensure sample frequency of perf event attributes is non-zero

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commit 4bbaf2584b86b0772413edeac22ff448f36351b1 upstream.

Correct a trinity finding for the perf_event_open() system call with
a perf event attribute structure that uses a frequency but has the
sampling frequency set to zero.  This causes a FP divide exception during
the sample rate initialization for the hardware sampling facility.

Fixes: 8c069ff4bd606 ("s390/perf: add support for the CPU-Measurement Sampling Facility")
Cc: stable@vger.kernel.org # 3.14+
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hendrik Brueckner 2018-05-03 15:56:15 +02:00 committed by Greg Kroah-Hartman
parent 9c32e0d365
commit 55b21399d8
1 changed files with 4 additions and 0 deletions
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4
arch/s390/kernel/perf_cpum_sf.c
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@ -744,6 +744,10 @@ static int __hw_perf_event_init(struct perf_event *event)
*/
rate = 0;
if (attr->freq) {
if (!attr->sample_freq) {
err = -EINVAL;
goto out;
}
rate = freq_to_sample_rate(&si, attr->sample_freq);
rate = hw_limit_rate(&si, rate);
attr->freq = 0;