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 4B01919B3FF; Tue, 15 Oct 2024 11:59:07 +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=1728993547; cv=none; b=W4arqhqK0vUxfFxy7G1lwwobdJ1v7gZ/Uy1SaeYhalJmZRFgbrihNw4W69O7sIY6Bkh+oMeAaABcB5vrIcpneWygs4EIBAbj3dmRfI7PTBcsF1a+A24s7Mg5IEyT7hJ2LB9LuVUS8HfxnRgsjo3QLqZMUt0+ZB7heC2vlJQvnhY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728993547; c=relaxed/simple; bh=R+DMvKMpszcPGiIeCFIzpbgf35HnYgpMXAg3pcp3cmI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=N7YuqKkkvrfm9D8ayu+Jamlwmo0oOYFBF9tNIwPqLwJ3weFpVTuQRoGrAztNTgf3tTgmj+0aRChXnGRlEsR9oc0CvGPgc/E+RTes8xwlJ+y2jg/UCKUav2ez3eznSOwZQDHDKAYGxdY5LoYao3tpQnChbdJNaeePnAynvUqqNhQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=x6xjO4vL; 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="x6xjO4vL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFD14C4CEC6; Tue, 15 Oct 2024 11:59:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728993547; bh=R+DMvKMpszcPGiIeCFIzpbgf35HnYgpMXAg3pcp3cmI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x6xjO4vLgudZfVNYLrct1iLGJb7ML0klapN55EQ2nVuTvy72M2/O71G3wCX5793KV GjKIAFeR1O1/bYaCLgxRIBeITgGPXXEEb78aE14rmRp1KIUL+PsdSkdZfHyRs1qaJr MLqgwko9uWh/7QTLroIhY6rA/ppbg+GPhOOUmq3o= 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 5.15 417/691] net: sched: consistently use rcu_replace_pointer() in taprio_change() Date: Tue, 15 Oct 2024 13:26:05 +0200 Message-ID: <20241015112456.893827584@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015112440.309539031@linuxfoundation.org> References: <20241015112440.309539031@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-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 4a0986843fb5d..49831bd6a37d5 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1599,7 +1599,9 @@ 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