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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 24D16C388F7 for ; Thu, 5 Nov 2020 23:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D12582083B for ; Thu, 5 Nov 2020 23:09:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604617793; bh=YG+T/KjOLKB+FKkyIhUQg8laeCA5qTCVg+kbJd/OhfI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=T5c0RofrfeF+NFxLrgQA7BHlKQqWSdKI1/p6UtrYG02APMwof7ByQwqVlSdrOZYAQ 2TPVGsgL7nHuCQn8wP67w5iqFRE1Eres/XrUtRvvRiuJR/1Fbjk0WOoCfWrqd/Qsvq hg43roZRoUf/LeRuRdfVPZosoRKgkBiHn5GEtaK0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732802AbgKEXJv (ORCPT ); Thu, 5 Nov 2020 18:09:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:34538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732698AbgKEXJa (ORCPT ); Thu, 5 Nov 2020 18:09:30 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-104-11.bvtn.or.frontiernet.net [50.39.104.11]) (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 282F622243; Thu, 5 Nov 2020 23:09:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604617770; bh=YG+T/KjOLKB+FKkyIhUQg8laeCA5qTCVg+kbJd/OhfI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mJXY9LLgj98lRjmdF6iLKKY2jR9WKMUTqvRKSvmwrGAIrsLN2B2hifArBS+L9LQfO VlwQsk5UFircvmhCm+A9/8a783Bkgv/xO83tkpn3hmeAk5OQwP/e5RnDGxkus6jV5O O+YDCEi0jHuZjZgum3U5tc6eY/iGIWRmHt2z2K/Y= 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, 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 16/16] srcu: Take early exit on memory-allocation failure Date: Thu, 5 Nov 2020 15:09:21 -0800 Message-Id: <20201105230921.19017-16-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20201105230856.GA18904@paulmck-ThinkPad-P72> References: <20201105230856.GA18904@paulmck-ThinkPad-P72> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" It turns out that init_srcu_struct() can be invoked from usermode tasks, and that fatal signals received by these tasks can cause memory-allocation failures. These failures are not handled well by init_srcu_struct(), so much so that NULL pointer dereferences can result. This commit therefore causes init_srcu_struct() to take an early exit upon detection of memory-allocation failure. Link: https://lore.kernel.org/lkml/20200908144306.33355-1-aik@ozlabs.ru/ Reported-by: Alexey Kardashevskiy Tested-by: Alexey Kardashevskiy Signed-off-by: Paul E. McKenney --- kernel/rcu/srcutree.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index c13348e..6f7880a 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -177,11 +177,13 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) INIT_DELAYED_WORK(&ssp->work, process_srcu); if (!is_static) ssp->sda = alloc_percpu(struct srcu_data); + if (!ssp->sda) + return -ENOMEM; init_srcu_struct_nodes(ssp, is_static); ssp->srcu_gp_seq_needed_exp = 0; ssp->srcu_last_gp_end = ktime_get_mono_fast_ns(); smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */ - return ssp->sda ? 0 : -ENOMEM; + return 0; } #ifdef CONFIG_DEBUG_LOCK_ALLOC -- 2.9.5