4.9-stable review patch. If anyone has any objections, please let me know.
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From: Hendrik Brueckner brueckner@linux.ibm.com
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
--- arch/s390/kernel/perf_cpum_sf.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -739,6 +739,10 @@ static int __hw_perf_event_init(struct p */ 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;