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Thu, 13 Aug 2026 07:08:17 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 13 Aug 2026 07:08:17 +0000 (GMT) From: Thomas Richter To: linux-s390@vger.kernel.org Cc: Thomas Richter Subject: [PATCH] s390/pai: Handle multiple PMU stop callback invocations Date: Thu, 13 Aug 2026 09:08:15 +0200 Message-ID: <20260813070815.2692398-1-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=AMtp2X5w c=1 sm=1 tr=0 ts=6a7d6d66 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=b6_6n78pCtPly934600A:9 X-Proofpoint-GUID: pM1peSR0c6Vxw3zqTvtvi6r_auxJiIqQ X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEzMDA0NyBTYWx0ZWRfX8VODgqpNxLIN IV0CHOP41hwFqdNEb07t1aqOypsGM+1yGQAOFZgfUn4kFsdczclPsEpb0KEfpOxojCyPijTkO9i wsRYf62F3OpPtYuzinNNlxjy/GGNJdRr8KtoVjkLKGFvkQWrmemYP973n015VqT91wJTFr9x+Mg 5DXrShniutmQUwmrSeoUVw/3rQOPRFhhI7iqTG0oLGBZyPpoNrMo0Q5OpsuK+pDH6YFKEyCWOU7 8Ng9E1p2JDLp18Y38AH1OM69VZXK7Jpqb+XpLKDNI2NHdEu7I7R/CuKhA6Y5PyVl8kwCzxJxqG7 9kiidoh7ZncqqQet+lIwzsTf8b1GdluIlSI5L70UQu2usObbOqpVGt5yz5IVcEs/QX8jf2PcNoR IJkoQNRcLCXFFL01JyV+3CqFy3hWoIw9xkG+Qg4+Xq/GFchT0LctomAxehQOXNjJi8QVsWjt5w4 uAkhE098n1T7T1hU8WA== X-Proofpoint-ORIG-GUID: pM1peSR0c6Vxw3zqTvtvi6r_auxJiIqQ X-Proofpoint-Spam-Info: AW1haW4tMjYwODEzMDA0NyBTYWx0ZWRfX87egVBbTqj1a rFz8KEMMkBy23VZlcjS0EwBCdiU5JB37R7wJVnxkP1m1zw5cntRwQbjbzU7Zi1qWSrlNfja5/d+ zVg4wTOiIpYxSCvkNERyDv/lNRosOAY= 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=2026-08-13_02,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 impostorscore=0 phishscore=0 spamscore=0 bulkscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608130047 Handle the following scenario: The kernel protects itself against a very high sampling load and throttles the sampling using: perf_event_throttle() --> PMU->stop() Shortly later the scheduler may terminate the task and removes it from the CPU. It again calls PMU->stop() which results in two invocations of PMU->stop() called back to back. Protect against this and check the PERF_HES_STOPPED bit on function entry. If it is already set return. Clear bit PERF_HES_STOPPED in PMU->start(). # Cc: stable@vger.kernel.org # v6.19+ Fixes: ac03223f0723 ("s390/pai_crypto: Add common pai_stop() function") Signed-off-by: Thomas Richter --- arch/s390/kernel/perf_pai.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/s390/kernel/perf_pai.c b/arch/s390/kernel/perf_pai.c index 1e5a1f1cc68a..f6790f658f21 100644 --- a/arch/s390/kernel/perf_pai.c +++ b/arch/s390/kernel/perf_pai.c @@ -484,6 +484,7 @@ static void pai_start(struct perf_event *event, int flags, cpump->event = event; } } + event->hw.state &= ~PERF_HES_STOPPED; } static void paicrypt_start(struct perf_event *event, int flags) @@ -530,6 +531,13 @@ static void pai_stop(struct perf_event *event, int flags) struct pai_mapptr *mp = this_cpu_ptr(pai_root[idx].mapptr); struct pai_map *cpump = mp->mapptr; + /* Cope with multiple invocations: + * 1. perf_event_throttle() --> PMU->stop() + * 2. task schedules out --> PMU->stop() + * Check for event already stopped. + */ + if (event->hw.state & PERF_HES_STOPPED) + return; if (!event->attr.sample_period) { /* Counting */ pai_pmu[idx].pmu->read(event); } else { /* Sampling */ -- 2.55.0