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Thu, 27 Aug 2026 06:46:37 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 27 Aug 2026 06:46:37 +0000 (GMT) From: Thomas Richter To: linux-s390@vger.kernel.org Cc: Thomas Richter Subject: [PATCH] s390/pai: Prevent ioctl(PERF_EVENT_IOC_REFRESH) Date: Thu, 27 Aug 2026 08:46:12 +0200 Message-ID: <20260827064612.3161950-1-tmricht@linux.ibm.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=TfimcxQh c=1 sm=1 tr=0 ts=6a8fdd52 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=32-ppuM1j2JskDvDLfMA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwODI3MDA1MiBTYWx0ZWRfX38vjLO0jdZI4 YBvZkw/QkxsN3d67douAYaDJp9E/j1wGPdtokeSoYAVTJqn3puJFebp+iWA6HLMsfYQNq2sOXBw rKrgxJI95ZTdeYmslzay91AjedVPaC4= X-Proofpoint-GUID: kpwUMfBcPu_GyXyNud2lzZqIaUrod4Y8 X-Proofpoint-ORIG-GUID: kpwUMfBcPu_GyXyNud2lzZqIaUrod4Y8 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI3MDA1MiBTYWx0ZWRfX/4D06H4nBLh+ 9vqyAy/5UTTGOz3xr76exr+JYbrkEUNk7YG6Hd4NHv4sKUQ5IzJCvLx6RZPX9l9BlwQ023skmQe Lm8Xg5W+L0Xj6focuvOFc+vJZkFM2yduQRn+cgQN5T613NPLNgSXTqz67dCq3ISfvLSRBCkHs9Z qdMI9exRcM/vzTrNXZMYrM3N2eQpJYp1ydsWnlNPa0xXBwsSLowejUu7liy+MoU72ZhJ151Re+h XmIgsJlxPKQL40Hg9tVbrz7bo0PF9Q2n3c7bJ1r7b4YMEyY7Cv3w+SD7i333CE36QWnTbByjAhZ X6FmJUDhbs95D/Do8jYYv7rqmFVH8uFZsoE4nAbT7cz3taHsKMJnugfE5CYkgMgnSAFIlFmoxFn oOsdn9NidMN+eOlGchCVBjPKm1uDvN9ORJpac4LWEktx8iWfmNlK81JmnGR4J7KRSd9CfXfUiLM vv8cDd53kywHbYAJmag== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-27_03,2026-08-26_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 spamscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 phishscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608270052 Prevent this ioctl(fd, PERF_EVENT_IOC_REFRESH, XXX) to take effect. PAI PMU events CRYPTO_ALL and NNPA_ALL are designed to read out the changed counter values at schedule out time, when these events have been installed system wide. Then they use CPU-context. If an application issues ioctl(fd, PERF_EVENT_IOC_REFRESH, XXX) it expects to read out samples after XXX hits. The PAI PMUs do that read operation and then reset the values because it expects a context switch out. This contradicts the readout at next schedule out time. The reported result is too low. Therefore prevent this call ioctl(PERF_EVENT_IOC_REFRESH) right now. Signed-off-by: Thomas Richter --- arch/s390/kernel/perf_pai.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/s390/kernel/perf_pai.c b/arch/s390/kernel/perf_pai.c index 05f74d74fad1..3e972d940100 100644 --- a/arch/s390/kernel/perf_pai.c +++ b/arch/s390/kernel/perf_pai.c @@ -666,6 +666,8 @@ static void pai_have_sample(struct perf_event *event, struct pai_map *cpump) if (!event) /* No event active */ return; + event->pending_kill = 0; /* prevent ioctl(IOC_REFRESH) */ + atomic_set(&event->event_limit, 0); pp = &pai_pmu[PAI_PMU_IDX(event)]; rawsize = pai_copy(cpump->save, cpump->area, pp, (unsigned long *)PAI_SAVE_AREA(event), -- 2.55.0