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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BEDAC3A59B for ; Fri, 30 Aug 2019 16:36:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE2A92342C for ; Fri, 30 Aug 2019 16:36:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="vM1+9Vta" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728195AbfH3Qgv (ORCPT ); Fri, 30 Aug 2019 12:36:51 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:41425 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728173AbfH3Qgt (ORCPT ); Fri, 30 Aug 2019 12:36:49 -0400 Received: by mail-pg1-f193.google.com with SMTP id x15so3797836pgg.8 for ; Fri, 30 Aug 2019 09:36:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=6foCHXYvGc/YUv+C7UREe6hicJoeLXUOk4RCFm7CD8U=; b=vM1+9Vtan3m+Dx2GCYwwzu54AD6Ybxe5HZPpHkb++iFYXQsxAreaQngONIGaas9fk1 5g9UAXvBQVgfBQ7pRjr9WCno1ofr7z//vfjfwwOkZDjFAZvmj8fAqRfBQnTlsP+K8aMC 3F/M8QRJg8K94LQ5q8rYJgSWuAclLWgkdXCFE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6foCHXYvGc/YUv+C7UREe6hicJoeLXUOk4RCFm7CD8U=; b=UO/9z8KI9s9RpYcaAP1k7Ef1cfzF6Fh+HcRwH72kpRdW4lJ83tUDLqu31wAiY9irkB Z5sUIk8xveiX+5lHcRHdBPhdkZ9In1uaWPRJcTnKixFNgE/elrqLS67HkwLczzk+qcXB IEFRcgAwa+jO3h5FSTmk+hw/MoCWAHkoobutAIDAE3h51T7X5WKSReDwcjLN2KEDl6oi Bdz2B8SJuoRZ7Yg0fXusEUBBCs+iCSlm8Hsu9A7sX71c0nrstfP2jH2kJSlul3graxgq uyqiinNlMGZkXgXrFHvszt//aQEb+2TDN+zrGJPkcdT0JjN4wUuNJsGiwPnJpweb6Nxu xnDQ== X-Gm-Message-State: APjAAAVFOzQiH7q5iGGvW7Se6SQNFOnUxpktENMPHZR0lplSGu9068Fw ynrgZ+r1j9/c4KWRgRQ9Ut7P1XiVBLc= X-Google-Smtp-Source: APXvYqyfyCzAysxf821xWN8fbyp1VftaNHPBq9mcl3pQd/MSyGep+IAVXGQIOsVMqA5koDPpakOFog== X-Received: by 2002:a63:e907:: with SMTP id i7mr13492018pgh.84.1567183008166; Fri, 30 Aug 2019 09:36:48 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id j74sm6114080pje.14.2019.08.30.09.36.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Aug 2019 09:36:47 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , byungchul.park@lge.com, Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , "Paul E. McKenney" , rcu@vger.kernel.org, Steven Rostedt Subject: [PATCH v2 -rcu dev 3/5] rcu/tree: Add support for debug_objects debugging for kfree_rcu() Date: Fri, 30 Aug 2019 12:36:31 -0400 Message-Id: <20190830163633.104099-4-joel@joelfernandes.org> X-Mailer: git-send-email 2.23.0.187.g17f5b7556c-goog In-Reply-To: <20190830163633.104099-1-joel@joelfernandes.org> References: <20190830163633.104099-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make use of RCU's debug_objects debugging support (CONFIG_DEBUG_OBJECTS_RCU_HEAD) similar to call_rcu() and other flavors. We queue the object during the kfree_rcu() call and dequeue it during reclaim. Tested that enabling CONFIG_DEBUG_OBJECTS_RCU_HEAD successfully detects double kfree_rcu() calls. Signed-off-by: Joel Fernandes (Google) --- kernel/rcu/tree.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2e1772469de9..de13805d1bd0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2757,6 +2757,7 @@ static void kfree_rcu_work(struct work_struct *work) for (; head; head = next) { next = head->next; /* Could be possible to optimize with kfree_bulk in future */ + debug_rcu_head_unqueue(head); __rcu_reclaim(rcu_state.name, head); cond_resched_tasks_rcu_qs(); } @@ -2876,6 +2877,13 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) if (rcu_scheduler_active != RCU_SCHEDULER_RUNNING) return kfree_call_rcu_nobatch(head, func); + if (debug_rcu_head_queue(head)) { + /* Probable double kfree_rcu() */ + WARN_ONCE(1, "kfree_call_rcu(): Double-freed call. rcu_head %p\n", + head); + return; + } + head->func = func; local_irq_save(flags); /* For safely calling this_cpu_ptr(). */ -- 2.23.0.187.g17f5b7556c-goog