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=-9.8 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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 91002C3A5A3 for ; Tue, 27 Aug 2019 19:02:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6860D21881 for ; Tue, 27 Aug 2019 19:02:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="Ci9p+TaN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730984AbfH0TCh (ORCPT ); Tue, 27 Aug 2019 15:02:37 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:34418 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730988AbfH0TCQ (ORCPT ); Tue, 27 Aug 2019 15:02:16 -0400 Received: by mail-pg1-f194.google.com with SMTP id n9so5185pgc.1 for ; Tue, 27 Aug 2019 12:02:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=message-id:from:to:cc:subject:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=1kV5KXYVJdyv65Hnx+nvfjLRXv6tCDCLMRGD0rrK31I=; b=Ci9p+TaNeqJRpdKmgjycDdZ1qGXv1XZJh049m7fUK6vIeeZsUv9/O/uy0CCsXAu7Sd P5jbOxozxX45q2CJYfbeMhDBp6qxOp9Y1bkpQvUUbYaPjeQGViihVHZ6CHfeUmp9ZXdj s76MwmIqSPfhAtIglSJK8Oq92XskicAPyN+1M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:from:to:cc:subject:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=1kV5KXYVJdyv65Hnx+nvfjLRXv6tCDCLMRGD0rrK31I=; b=HYaN7iVg2jUaWVAdmo8muTBdLJl2S9ONR1H8qI4T9OkpVZYKbkSWfRyeoX0cPvmH0P ned182h8GjQX2XJB1HfMwXQHOMJvqh4qiHApg4gBuRzXCc2NmxBPjOGCCzXm0rMLRfwO 8Gn+yNZybwm61GQt6EQG5gfueGmH9ioWudYj53D335J6TDWTuGyRkfNOJhwe+2Tch+wF BZnCllUFlHgstTi7e9OCW2b3kGxJNKWNyMp5hEb/JkBswc03hlX8p/UD50fX8NlQ/rLZ 3Wm9Jh0zUfvbG9QVmLiBITgft69zMCWibANA1+xJdd33gGO5aSf0XnaYXhX066Wqzayn M7CA== X-Gm-Message-State: APjAAAVFVmiEcZaubYUEOdVrqOXUXBXR2+QaTcCgnkj0FrSNktjl8EdK tNIjN9pYf+r/QoYjfikaNqumrA== X-Google-Smtp-Source: APXvYqwEDpu+LRH81GOKlAAgs8mPTOzvlBj1YFIBm2lbfeOMjXcJ7fuw83pZGhoFWp6qscf1k3vrxw== X-Received: by 2002:a17:90a:ff04:: with SMTP id ce4mr183366pjb.77.1566932535866; Tue, 27 Aug 2019 12:02:15 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id k14sm33196pfi.98.2019.08.27.12.02.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Aug 2019 12:02:15 -0700 (PDT) Message-ID: <5d657e37.1c69fb81.54250.01df@mx.google.com> X-Google-Original-Message-ID: 1566932472104184@cam.corp.google.com From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , byungchul.park@lge.com, Josh Triplett , Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers , "Paul E. McKenney" , rcu@vger.kernel.org, Steven Rostedt , kernel-team@android.com Subject: [PATCH 3/5] rcu/tree: Add support for debug_objects debugging for kfree_rcu() Date: Tue, 27 Aug 2019 15:01:57 -0400 X-Mailer: git-send-email 2.23.0.187.g17f5b7556c-goog In-Reply-To: 156693247224727@cam.corp.google.com References: 156693247224727@cam.corp.google.com MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@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 9b9ae4db1c2d..64568f12641d 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(); } @@ -2868,6 +2869,13 @@ 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