From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heiko Carstens , Hendrik Brueckner , Martin Schwidefsky Subject: [PATCH 4.4 59/92] s390/cpum_sf: ensure sample frequency of perf event attributes is non-zero Date: Thu, 24 May 2018 11:38:36 +0200 Message-Id: <20180524093204.984626877@linuxfoundation.org> In-Reply-To: <20180524093159.286472249@linuxfoundation.org> References: <20180524093159.286472249@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hendrik Brueckner 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 Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- 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 @@ -744,6 +744,10 @@ 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;