From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD867EDEC49 for ; Wed, 13 Sep 2023 12:52:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240686AbjIMMwZ (ORCPT ); Wed, 13 Sep 2023 08:52:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240675AbjIMMwT (ORCPT ); Wed, 13 Sep 2023 08:52:19 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 438701BC9; Wed, 13 Sep 2023 05:52:15 -0700 (PDT) Received: from pps.filterd (m0353729.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 38DCnSN7018886; Wed, 13 Sep 2023 12:52:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=E0zARhDZbaDg3CggwhVYRBWdci5AOK6H4f5dxa6OpLk=; b=GeXWhSnHLh69CbaFh+9RBFn36gB60vOFRuY77+89zfgyfMB4wNjW4NNhJMKnCEPSVPnX CjrKDjVQ3B2jRmtuZeOWRmqGdS+TXwFQJpeel5HDFxeTbfR3wxpx2vM4lWWJ/4k2phtG C1pvbI0rAF/7bt607S/KArkQ+3+6/B6vSdnP2uJ6zABzTb6RgpalnwtwCvfj8Pa5Z6IB bKXxTsl2IbnNa1ffIraB4CoL0rJ+YP57yjMPdVmVShlparyfFXqRwIvGsSIqc6RoJmz4 n9U0U38jtepvSFe4FnreqTUnrwX77N8c2nyK4XdRbJ4+ScQyD98ZQVH0lLq3EJTyy7z3 Mw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3t3dasrcje-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 Sep 2023 12:52:12 +0000 Received: from m0353729.ppops.net (m0353729.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 38DCh1mc030324; Wed, 13 Sep 2023 12:52:12 GMT Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3t3dasrchy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 Sep 2023 12:52:12 +0000 Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 38DBJgDm002410; Wed, 13 Sep 2023 12:52:11 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 3t158karsu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 Sep 2023 12:52:11 +0000 Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 38DCq8rf40043130 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Sep 2023 12:52:08 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 683212004B; Wed, 13 Sep 2023 12:52:08 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 082A220040; Wed, 13 Sep 2023 12:52:08 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 13 Sep 2023 12:52:07 +0000 (GMT) From: Thomas Richter To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org, sumanthk@linux.ibm.com, irogers@google.com, dengler@linux.ibm.com Cc: svens@linux.ibm.com, gor@linux.ibm.com, hca@linux.ibm.com, Thomas Richter Subject: [PATCH] perf jevent: fix core dump on software events on s390 Date: Wed, 13 Sep 2023 14:51:57 +0200 Message-Id: <20230913125157.2790375-1-tmricht@linux.ibm.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: SKDvXtND-Dl8lnfG6fbqUxQe1xpIb_fQ X-Proofpoint-ORIG-GUID: 4kgzq8EjvkxZTv_oqssvd1laGMOHsN-h X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-09-13_06,2023-09-13_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 mlxlogscore=999 clxscore=1011 suspectscore=0 spamscore=0 bulkscore=0 phishscore=0 mlxscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2308100000 definitions=main-2309130101 Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org Running commands such as # ./perf stat -e cs -- true Segmentation fault (core dumped) # ./perf stat -e cpu-clock-- true Segmentation fault (core dumped) # dump core. This should not happen as these events are defined even when no hardware PMU is available. Debugging this reveals this call chain: perf_pmus__find_by_type(type=1) +--> pmu_read_sysfs(core_only=false) +--> perf_pmu__find2(dirfd=3, name=0x152a113 "software") +--> perf_pmu__lookup(pmus=0x14f0568 , dirfd=3, lookup_name=0x152a113 "software") +--> perf_pmu__find_events_table (pmu=0x1532130) Now the pmu is "software" and it tries to find a proper table generated by the pmu-event generation process for s390: # cd pmu-events/ # ./jevents.py s390 all /root/linux/tools/perf/pmu-events/arch |\ grep -E '^const struct pmu_table_entry' const struct pmu_table_entry pmu_events__cf_z10[] = { const struct pmu_table_entry pmu_events__cf_z13[] = { const struct pmu_table_entry pmu_metrics__cf_z13[] = { const struct pmu_table_entry pmu_events__cf_z14[] = { const struct pmu_table_entry pmu_metrics__cf_z14[] = { const struct pmu_table_entry pmu_events__cf_z15[] = { const struct pmu_table_entry pmu_metrics__cf_z15[] = { const struct pmu_table_entry pmu_events__cf_z16[] = { const struct pmu_table_entry pmu_metrics__cf_z16[] = { const struct pmu_table_entry pmu_events__cf_z196[] = { const struct pmu_table_entry pmu_events__cf_zec12[] = { const struct pmu_table_entry pmu_metrics__cf_zec12[] = { const struct pmu_table_entry pmu_events__test_soc_cpu[] = { const struct pmu_table_entry pmu_metrics__test_soc_cpu[] = { const struct pmu_table_entry pmu_events__test_soc_sys[] = { # However event "software" is not listed, as can be seen in the generated const struct pmu_events_map pmu_events_map[]. So in function perf_pmu__find_events_table(), the variable table is initialized to NULL, but never set to a proper value. The function scans all generated &pmu_events_map[] tables, but no table matches, because the tables are s390 CPU Measurement unit specific: i = 0; for (;;) { const struct pmu_events_map *map = &pmu_events_map[i++]; if (!map->arch) break; --> the maps are there because the build generated them if (!strcmp_cpuid_str(map->cpuid, cpuid)) { table = &map->event_table; break; } --> Since no matching CPU string the table var remains 0x0 } free(cpuid); if (!pmu) return table; --> The pmu is "software" so it exists and no return --> and here perf dies because table is 0x0 for (i = 0; i < table->num_pmus; i++) { ... } return NULL; Fix this and do not access the table variable. Instead return 0x0 which is the same return code when the for-loop was not successful. Output after: # ./perf stat -e cs -- true Performance counter stats for 'true': 0 cs 0.000853105 seconds time elapsed 0.000061000 seconds user 0.000827000 seconds sys # ./perf stat -e cpu-clock -- true Performance counter stats for 'true': 0.25 msec cpu-clock # 0.341 CPUs utilized 0.000728383 seconds time elapsed 0.000055000 seconds user 0.000706000 seconds sys # ./perf stat -e cycles -- true Performance counter stats for 'true': cycles 0.000767298 seconds time elapsed 0.000055000 seconds user 0.000739000 seconds sys # Signed-off-by: Thomas Richter --- tools/perf/pmu-events/jevents.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py index a7e88332276d..72ba4a9239c6 100755 --- a/tools/perf/pmu-events/jevents.py +++ b/tools/perf/pmu-events/jevents.py @@ -991,7 +991,7 @@ const struct pmu_events_table *perf_pmu__find_events_table(struct perf_pmu *pmu) } } free(cpuid); - if (!pmu) + if (!pmu || !table) return table; for (i = 0; i < table->num_pmus; i++) { -- 2.41.0