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 C0B1E1ED38 for ; Tue, 25 Jul 2023 11:28:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19BA4C433C7; Tue, 25 Jul 2023 11:28:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690284486; bh=0Aw/59vnlWzcu5s0Nje/aDuhJCutSPF7l2kyhEwJnuI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=izyvumgWh4OuaB6ngb6RzC8zTMLU2dig6R0WTdlN5uo1F/p6U2hT+jt9cPW0L+7Dg tAXEpu5QYobhIg3scv3ar+Z9KPBh5mJbEjfBPHY3RVMEZWsu8nPKQCbT1PCPqnqKgS X5RT4/o10pAAEs2xIH54VbG+1E7Btz44gZ8UoaYc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Pedro Tammela , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 372/509] net/sched: make psched_mtu() RTNL-less safe Date: Tue, 25 Jul 2023 12:45:11 +0200 Message-ID: <20230725104610.749305626@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104553.588743331@linuxfoundation.org> References: <20230725104553.588743331@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Pedro Tammela [ Upstream commit 150e33e62c1fa4af5aaab02776b6c3812711d478 ] Eric Dumazet says[1]: ------- Speaking of psched_mtu(), I see that net/sched/sch_pie.c is using it without holding RTNL, so dev->mtu can be changed underneath. KCSAN could issue a warning. ------- Annotate dev->mtu with READ_ONCE() so KCSAN don't issue a warning. [1] https://lore.kernel.org/all/CANn89iJoJO5VtaJ-2=_d2aOQhb0Xw8iBT_Cxqp2HyuS-zj6azw@mail.gmail.com/ v1 -> v2: Fix commit message Fixes: d4b36210c2e6 ("net: pkt_sched: PIE AQM scheme") Suggested-by: Eric Dumazet Signed-off-by: Pedro Tammela Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230711021634.561598-1-pctammela@mojatatu.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/pkt_sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h index ba781e0aaf566..e186b2bd8c860 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -136,7 +136,7 @@ extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1]; */ static inline unsigned int psched_mtu(const struct net_device *dev) { - return dev->mtu + dev->hard_header_len; + return READ_ONCE(dev->mtu) + dev->hard_header_len; } static inline struct net *qdisc_net(struct Qdisc *q) -- 2.39.2