From patchwork Tue Aug 22 02:38:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 136513 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b82d:0:b0:3f2:4152:657d with SMTP id z13csp3553631vqi; Tue, 22 Aug 2023 04:20:48 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEYSyuffvXyZwZmd95BFQFR4Osb9mVt71qby4C2oAWKVbgF2SKBmhpS0ttxExel7+IWD83R X-Received: by 2002:aa7:d952:0:b0:523:33eb:1103 with SMTP id l18-20020aa7d952000000b0052333eb1103mr7352286eds.14.1692703247851; Tue, 22 Aug 2023 04:20:47 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1692703247; cv=none; d=google.com; s=arc-20160816; b=PxNj6fJZFqiaXbh30O6Vh8az8nSlzKCSIuD18/sTCfKRwJx/8wsNyI0ABtvF7zEspl ZkR6pD4fSoQj2Ljj08CmcK+7BFXyaWAwNscbSB/3OxDq/q6h//ep/1SkacCnDcKFXk7N xf2d0W+Nd5Oh1+ox7Zkh3SEOI7yqW4JOjPFZbJJ+6jJR6vTwkPSABMk1jI/8guY1RjyY huhUEXSSG1z71FSxW6za6sUfoUxgdgSz8EJFW17kBrr3iudCsGOCEXD6UeaAoB1OZ68v SthY+CpXm+uBP/rZ+ck+XpD7JEN5Wv8G4BTpW+v0AxsRmuElPtI4Kc2RibxLBRyY8Eo5 hTOA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:references:subject:cc:to:from:date :user-agent:message-id; bh=LGNuAQXNMn+HKXFuSc4OsdRQ+TrGLJN+PkUjGQHnrmk=; fh=0YPng9sAhhVGht5GuLC6X9b/s19iQXlsFdA02gxc2XQ=; b=Q6MRhOQL06e/CPA0NSuMmL/bAA017cngQ2RSLmEjeerXK+7GV48YPmDLTN7V9XdsIm cOBhKgbwflYcEGxtzVLCZcCogTG0hOhQRhGgrXplKYbgd/VQ11w2CawN+va4fApVseSW 2mdJpgJUORIkH43u6anZ49n44kX+/60A9aljFaV/cuwirEf2rmNlJFC4emJZiNBC+W0s nWHTKAx8RZY1BZRiTpr0/w4TZ4L40y+PV5qvIl3H4aw3ufq4uLgGvECRWFTFhoHus7da 8JkL9nt+Pt5uHX+8aLTQR3SJ51pB1spEFjVxXlmQSHzLszJhB+paD7Xeg7hvswAeLmBL MTGQ== ARC-Authentication-Results: i=1; mx.google.com; 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 Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id r3-20020a056402034300b00525950d5f6bsi7412866edw.130.2023.08.22.04.20.23; Tue, 22 Aug 2023 04:20:47 -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; 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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232285AbjHVCic (ORCPT + 99 others); Mon, 21 Aug 2023 22:38:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42382 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232265AbjHVCi3 (ORCPT ); Mon, 21 Aug 2023 22:38:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77F1D184 for ; Mon, 21 Aug 2023 19:38:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0E27764372 for ; Tue, 22 Aug 2023 02:38:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 673DCC433C7; Tue, 22 Aug 2023 02:38:25 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1qYHI1-001bZF-1S; Mon, 21 Aug 2023 22:38:41 -0400 Message-ID: <20230822023841.262172484@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 21 Aug 2023 22:38:04 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton , , , Zheng Yejian Subject: [for-linus][PATCH 1/8] tracing: Fix cpu buffers unavailable due to record_disabled missed References: <20230822023803.605698724@goodmis.org> MIME-Version: 1.0 X-Spam-Status: No, score=-1.6 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE, SPF_PASS 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: INBOX X-GMAIL-THRID: 1774928000386680231 X-GMAIL-MSGID: 1774928000386680231 From: Zheng Yejian Trace ring buffer can no longer record anything after executing following commands at the shell prompt: # cd /sys/kernel/tracing # cat tracing_cpumask fff # echo 0 > tracing_cpumask # echo 1 > snapshot # echo fff > tracing_cpumask # echo 1 > tracing_on # echo "hello world" > trace_marker -bash: echo: write error: Bad file descriptor The root cause is that: 1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask()); 2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped with 'tr->max_buffer.buffer', then the 'record_disabled' became 0 (see update_max_tr()); 3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1; Then array_buffer and max_buffer are both unavailable due to value of 'record_disabled' is not 0. To fix it, enable or disable both array_buffer and max_buffer at the same time in tracing_set_cpumask(). Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com Cc: Cc: Cc: Fixes: 71babb2705e2 ("tracing: change CPU ring buffer state from tracing_cpumask") Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b8870078ef58..b0e8eb6ea8ac 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5277,11 +5277,17 @@ int tracing_set_cpumask(struct trace_array *tr, !cpumask_test_cpu(cpu, tracing_cpumask_new)) { atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled); ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu); +#ifdef CONFIG_TRACER_MAX_TRACE + ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu); +#endif } if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) && cpumask_test_cpu(cpu, tracing_cpumask_new)) { atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled); ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu); +#ifdef CONFIG_TRACER_MAX_TRACE + ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu); +#endif } } arch_spin_unlock(&tr->max_lock);