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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 9745FC2D0BF for ; Tue, 10 Dec 2019 04:11:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C8A42080D for ; Tue, 10 Dec 2019 04:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575951115; bh=23X8As3LtLzSWfubNif9hGJNq8LPzWRDyu6nOQWPES8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eQTApHZWqYqLvYgs97jJChCo0CpPHSQTnMdjchyG3HqqHHxcstdVAU1qBLnpJ2BCJ xxqdFiYFvPpJw201FSUkcvNiCQddX71yrmu42f5jHgBs0DLaNGb0qCxU1YjzSHpRu5 ZAyqQbmjspElFAsG6pNo66wRUldUrtvYoDqIMoiA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727004AbfLJELx (ORCPT ); Mon, 9 Dec 2019 23:11:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:44942 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726691AbfLJELx (ORCPT ); Mon, 9 Dec 2019 23:11:53 -0500 Received: from paulmck-ThinkPad-P72.home (199-192-87-166.static.wiline.com [199.192.87.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0F2D7214AF; Tue, 10 Dec 2019 04:11:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575951112; bh=23X8As3LtLzSWfubNif9hGJNq8LPzWRDyu6nOQWPES8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VQ/uSqWQol1tLiWbTBj+ozd2ZzQNeZo/RbyECXe+Mnpg30/OkEZ++d7rsChxyU+3M CG/G7cQzqTbOpGLp8OZZwmj7JwCBhCfzrMhus/0fAHRVXb7tv4hkRSD5EWOfyG4Y8g USrYAcU6mG0EXHDocUbb4/7MtFzsR3JT7cB9vQLY= From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E . McKenney" Subject: [PATCH tip/core/rcu 5/7] rcu: Add support for debug_objects debugging for kfree_rcu() Date: Mon, 9 Dec 2019 20:11:45 -0800 Message-Id: <20191210041147.3181-5-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20191210041118.GA3115@paulmck-ThinkPad-P72> References: <20191210041118.GA3115@paulmck-ThinkPad-P72> Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: "Joel Fernandes (Google)" 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); -- 2.9.5