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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 CD9D3C35244 for ; Sat, 25 Jan 2020 10:46:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABB0E218AC for ; Sat, 25 Jan 2020 10:46:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730088AbgAYKqH (ORCPT ); Sat, 25 Jan 2020 05:46:07 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:44181 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727215AbgAYKm4 (ORCPT ); Sat, 25 Jan 2020 05:42:56 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1ivItx-0008Of-IW; Sat, 25 Jan 2020 11:42:53 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id B1B6F1C1A79; Sat, 25 Jan 2020 11:42:44 +0100 (CET) Date: Sat, 25 Jan 2020 10:42:44 -0000 From: "tip-bot2 for Joel Fernandes (Google)" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/rcu] rcu: Add support for debug_objects debugging for kfree_rcu() Cc: "Joel Fernandes (Google)" , "Paul E. McKenney" , x86 , LKML MIME-Version: 1.0 Message-ID: <157994896449.396.2829071003515065139.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/rcu branch of tip: Commit-ID: e99637becb2e684bee2b9117f817f4d1346b8353 Gitweb: https://git.kernel.org/tip/e99637becb2e684bee2b9117f817f4d1346b8353 Author: Joel Fernandes (Google) AuthorDate: Sun, 22 Sep 2019 13:03:17 -07:00 Committer: Paul E. McKenney CommitterDate: Fri, 24 Jan 2020 10:24:31 -08:00 rcu: Add support for debug_objects debugging for kfree_rcu() This commit applies RCU's debug_objects debugging to the new batched kfree_rcu() implementations. The object is queued at the kfree_rcu() call and dequeued during reclaim. Tested that enabling CONFIG_DEBUG_OBJECTS_RCU_HEAD successfully detects double kfree_rcu() calls. Signed-off-by: Joel Fernandes (Google) [ paulmck: Fix IRQ per kbuild test robot feedback. ] Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a40fd58..0512221 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2749,6 +2749,7 @@ static void kfree_rcu_work(struct work_struct *work) for (; head; head = next) { next = head->next; // Potentially optimize with kfree_bulk in future. + debug_rcu_head_unqueue(head); __rcu_reclaim(rcu_state.name, head); cond_resched_tasks_rcu_qs(); } @@ -2855,6 +2856,12 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) spin_lock(&krcp->lock); // Queue the object but don't yet schedule the batch. + if (debug_rcu_head_queue(head)) { + // Probable double kfree_rcu(), just leak. + WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n", + __func__, head); + goto unlock_return; + } head->func = func; head->next = krcp->head; krcp->head = head; @@ -2866,6 +2873,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); } +unlock_return: if (krcp->initialized) spin_unlock(&krcp->lock); local_irq_restore(flags);