From patchwork Tue Jul 4 18:15:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 115883 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:9f45:0:b0:3ea:f831:8777 with SMTP id v5csp1396417vqx; Tue, 4 Jul 2023 11:29:28 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6dBstzJl6kTBpL5HDVZImCXFIaQTwG2hl6unTsT2egY5/tVCN19uIGajwuWFZJ9Md1lgEE X-Received: by 2002:a05:6a20:160e:b0:125:a12e:a918 with SMTP id l14-20020a056a20160e00b00125a12ea918mr14804532pzj.8.1688495367790; Tue, 04 Jul 2023 11:29:27 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1688495367; cv=none; d=google.com; s=arc-20160816; b=IWyX+Nc4C4dLeC+RSpUZRWku/aXgvOSlHt7JumoMbLN1TwwozNREYhv1ZsS2cQtCRO vzztUwVsYbDoruUoxN29+Ba1TxDaTrfWaSHyX3DZvvw1CR9Db4M75c4zXbLzuF8WF2rq eko99ECyCh86vkivh2e2zdPDN0aGfxYFPCtSzclDHKdDakae0rGxr24Bw0SdRmnxr3d9 o09gZkBlpmPygHRzhH7jga9EhIBGLbgpfty5+AVHmF6b/5U/uvJWFesftx4TZv73V3PX 0ur39be0eosD3q17CAvKTPeH0a8ss7NxhBBYum8sFOy1i7JqslwkWWnVH8SXwZAlDqxA DuAg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:sender:dkim-signature; bh=DSqYHV9aOqFyal3Tm/y/6ISIc1yWfppvT5nKEoCz+0I=; fh=WH2NMq1ZwQlWHP2vQD5QBaqV1bmF0l2QSlnqCnImEhk=; b=YTer76PrLWQKzX651BnMPzO11ru7Oo2lv1qhT1hd4ZgIklPvzYC9pHA/JUszKNjsHY zFWFwkTAM62dXjPE9AMOY3hFPyx3vfqkVzkZ+hklyHaJIm41Swb0TQsxPrVOCRNlSqPd jypNT+d73wuPzTminLW/t05N6yU7rKe49Arw/BTlVA7Yb9sD6yPp3R7zOwElWVG3hKKg XaHiKkkUmpFt2S/0g4OlDnY2KPA0gKSPiTWOZJqKSrkxBIp2knF3j1+eKLdlkbhnwbk+ bz6ALM91rWYqCY7kLpfXmAB6qLC3MJuURJKLBXYgBaV7K8TvvX1rLQcz3OTRvYiqJ3BC A60g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b=RIzLb7Ta; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id q8-20020a170902dac800b001b892b6cec9si5870356plx.150.2023.07.04.11.29.15; Tue, 04 Jul 2023 11:29:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b=RIzLb7Ta; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231406AbjGDSPW (ORCPT + 99 others); Tue, 4 Jul 2023 14:15:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230246AbjGDSPU (ORCPT ); Tue, 4 Jul 2023 14:15:20 -0400 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B83E10CA; Tue, 4 Jul 2023 11:15:19 -0700 (PDT) Received: by mail-pf1-x436.google.com with SMTP id d2e1a72fcca58-666e64e97e2so3003610b3a.1; Tue, 04 Jul 2023 11:15:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1688494519; x=1691086519; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:from:to:cc:subject:date:message-id:reply-to; bh=DSqYHV9aOqFyal3Tm/y/6ISIc1yWfppvT5nKEoCz+0I=; b=RIzLb7TawJkCpEJQbDIU8BXy4bWw/yGDH/7J/GYhKwiu9J7lCjupK3kiSYf4wa8mmr k1S4t1dw0herZTL6y2GQ0gHWwTa8UC0WK5FToGuAK2YcMP/3ohfSTzVenkWFlbGJ86hN MKsfx2j1EKkHnx8lt3ol6fJ4GG3adw7TNXGUbfYku6mADtMx1CjWo2Jf6HMkw7780dk6 tqd8+kUlaYOO7cioX/WxIOMd3wozhQMwShwujlMVOHJBOEkjc2u9ZAcV2sKFEsokDqjt Hd4ZSzaRKwOs2QZssxM25FsgBPLKcd0MbNnPY/eZDdut9cOkY7z2DTm6X4CSFdJJkqbX PztA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688494519; x=1691086519; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=DSqYHV9aOqFyal3Tm/y/6ISIc1yWfppvT5nKEoCz+0I=; b=Fufrmo3wrhQ7QCfw46PI8G0g24Fmj65lEK5yXkhklXgS+ykJzx4glNWBTDU7o6+6cI z6+2gkV3ZfzwMjTFtH5BmbNMiedB9Ity8UIHzon9/z9ECZ5w8dZSUg7rYLzvvYCa9h2Q hbOqqKSgxmQuEB3yiWUpWHxevDbZirnyvHHDlbIG6qc64JJROMUgHNFPe7xGKWLFyb6o HkEWENYZnpy/iCUQOXaGQ21JAki4O7DVXNOBZKSN8K0e6cOjtF/bEyJ0mIVvm9HroYBV CpLS+ukY52M6bqayzWw+AO00uuidwAXtc3uVGZoDKoIbquwiiEogE02lklTB0UrF/sPY GBMQ== X-Gm-Message-State: ABy/qLYRNrP4xUmZzWZI3OhBAeS5dlUJ08EdSzuMl2piOW18fJQUtW9k 2krupy/sGOsQvPN6kwp6OXQ= X-Received: by 2002:a05:6a00:2da3:b0:66a:2771:6c4d with SMTP id fb35-20020a056a002da300b0066a27716c4dmr15771360pfb.4.1688494518570; Tue, 04 Jul 2023 11:15:18 -0700 (PDT) Received: from bangji.hsd1.ca.comcast.net ([2601:647:6700:7f00:6b7:7112:19a1:fc15]) by smtp.gmail.com with ESMTPSA id u25-20020a62ed19000000b00682a839d0aesm1476717pfh.112.2023.07.04.11.15.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Jul 2023 11:15:18 -0700 (PDT) Sender: Namhyung Kim From: Namhyung Kim To: Peter Zijlstra , Ingo Molnar Cc: Mark Rutland , Alexander Shishkin , Arnaldo Carvalho de Melo , LKML , Kan Liang , Stephane Eranian , Greg Thelen , stable@vger.kernel.org Subject: [PATCH] perf/x86: Fix lockdep warning in for_each_sibling_event() on SPR Date: Tue, 4 Jul 2023 11:15:15 -0700 Message-ID: <20230704181516.3293665-1-namhyung@kernel.org> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog MIME-Version: 1.0 X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1770515718876617110?= X-GMAIL-MSGID: =?utf-8?q?1770515718876617110?= On SPR, the load latency event needs an auxiliary event in the same group to work properly. There's a check in intel_pmu_hw_config() for this to iterate sibling events and find a mem-loads-aux event. The for_each_sibling_event() has a lockdep assert to make sure if it disabled hardirq or hold leader->ctx->mutex. This works well if the given event has a separate leader event since perf_try_init_event() grabs the leader->ctx->mutex to protect the sibling list. But it can cause a problem when the event itself is a leader since the event is not initialized yet and there's no ctx for the event. Actually I got a lockdep warning when I run the below command on SPR, but I guess it could be a NULL pointer dereference. $ perf record -d -e cpu/mem-loads/uP true The code path to the warning is: sys_perf_event_open() perf_event_alloc() perf_init_event() perf_try_init_event() x86_pmu_event_init() hsw_hw_config() intel_pmu_hw_config() for_each_sibling_event() lockdep_assert_event_ctx() We don't need for_each_sibling_event() when it's a standalone event. Let's return the error code directly. Fixes: f3c0eba28704 ("perf: Add a few assertions") Reported-by: Greg Thelen Cc: stable@vger.kernel.org Signed-off-by: Namhyung Kim --- arch/x86/events/intel/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 0d09245aa8df..933fe4894c32 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3983,6 +3983,14 @@ static int intel_pmu_hw_config(struct perf_event *event) struct perf_event *leader = event->group_leader; struct perf_event *sibling = NULL; + /* + * The event is not fully initialized yet and no ctx is set + * for the event. Avoid for_each_sibling_event() since it + * has a lockdep assert with leader->ctx->mutex. + */ + if (leader == event) + return -ENODATA; + if (!is_mem_loads_aux_event(leader)) { for_each_sibling_event(sibling, leader) { if (is_mem_loads_aux_event(sibling))