From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EA2451C07DF; Tue, 15 Oct 2024 13:11:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728997899; cv=none; b=CrGo0gYHr5zDHXwel+czY7nL2ZqKFuRU0L+ZM2u+/48+mvhSOAkqK7ujQGfI59ZkGPqTaXgPsAdgwqlFd/xOZVMZJkx+5ocDrVDhc8gJ+fkggvCDlgcWMd0E+png+HYyIHon05aCyIqhhBKhepknz10m5T/6uxDzmL9Dmw4Zans= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728997899; c=relaxed/simple; bh=Z2u2nQVhYugad6c3hjw0N6bBIW8Ma7mVfEyMqz/WPV0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bIDdlyMlqVEcg8bK8DVWNqg4SfymQHXIRcqF0+zndSbvXbbx8ms2pO99povX2tRtS8msb7u0goGRAYmpctjbL4d0YkIcYiaEWyRFlpNkSIxeR0RUs2vJ24/lRUv/YkRJf4ja3/8Z3mXbm/bHlA4fYsE+ruhKNVRR1RjhyjvhPyI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VzoJuw9Q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VzoJuw9Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 625A4C4CEC6; Tue, 15 Oct 2024 13:11:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728997898; bh=Z2u2nQVhYugad6c3hjw0N6bBIW8Ma7mVfEyMqz/WPV0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VzoJuw9Q3a2EXyFwqdpIR7ef36ltE7Ouj8CjW9AWJs8AH0BOj5XMIkaoQ3+Azo6kb 1VbjiNdQeBSE7Du2sPn5fadLVni26Y/ZBqPKIHuCt3jpQdjehcxapKowv78A7eKf+1 X4VfKAPsYt5slGmh/H2YxZiBQ2wWNnB4mlnEcnrg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vinicius Costa Gomes , Dmitry Antipov , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 303/518] net: sched: consistently use rcu_replace_pointer() in taprio_change() Date: Tue, 15 Oct 2024 14:43:27 +0200 Message-ID: <20241015123928.682221309@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015123916.821186887@linuxfoundation.org> References: <20241015123916.821186887@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Antipov [ Upstream commit d5c4546062fd6f5dbce575c7ea52ad66d1968678 ] According to Vinicius (and carefully looking through the whole https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa once again), txtime branch of 'taprio_change()' is not going to race against 'advance_sched()'. But using 'rcu_replace_pointer()' in the former may be a good idea as well. Suggested-by: Vinicius Costa Gomes Signed-off-by: Dmitry Antipov Acked-by: Vinicius Costa Gomes Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sched/sch_taprio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index ec6b24edf5f93..04ed23b5f21b4 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1577,7 +1577,9 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, goto unlock; } - rcu_assign_pointer(q->admin_sched, new_admin); + /* Not going to race against advance_sched(), but still */ + admin = rcu_replace_pointer(q->admin_sched, new_admin, + lockdep_rtnl_is_held()); if (admin) call_rcu(&admin->rcu, taprio_free_sched_cb); } else { -- 2.43.0