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Commit 4bbaf258 authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Martin Schwidefsky
Browse files

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



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: 8c069ff4 ("s390/perf: add support for the CPU-Measurement Sampling Facility")
Cc: stable@vger.kernel.org # 3.14+
Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarHendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent de5cb6eb

arch/s390/kernel/perf_cpum_sf.c

+4 −0
Original line number Diff line number Diff line
@@ -753,6 +753,10 @@ 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;