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Message-Id: <20180521210507.731353876@linuxfoundation.org>
Date: Mon, 21 May 2018 23:11:38 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Heiko Carstens <heiko.carstens@...ibm.com>,
Hendrik Brueckner <brueckner@...ux.ibm.com>,
Martin Schwidefsky <schwidefsky@...ibm.com>
Subject: [PATCH 4.16 041/110] s390/cpum_sf: ensure sample frequency of perf event attributes is non-zero
4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hendrik Brueckner <brueckner@...ux.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@...r.kernel.org # 3.14+
Reviewed-by: Heiko Carstens <heiko.carstens@...ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@...ux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@...ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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
@@ -753,6 +753,10 @@ 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;
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