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 C62D41F941 for ; Fri, 21 Jul 2023 16:14:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A2C4C433C8; Fri, 21 Jul 2023 16:14:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689956095; bh=Ru8hm6NqA2nvAw6nJGy7+hiPaEPJSRba08pY4U56C3w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lAqpiIdaiuua+43M38EeyDl7gv0LQmTJ+dRdOWfzJQrkk8x6iASTbqytGf1vhBHca YR833MQ4OpGvJMgUy75N/A0MaNmfrrVKl0ywB7BQWSWyqe49QjhOV5xyWX7EggDxGS Xx3cwyVuxPRCi9MdYXlnu0NrUE28H7i4ToND/Azo= 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 6.4 102/292] net/sched: make psched_mtu() RTNL-less safe Date: Fri, 21 Jul 2023 18:03:31 +0200 Message-ID: <20230721160533.174347392@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160528.800311148@linuxfoundation.org> References: <20230721160528.800311148@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 7dba1c3a7b801..2465d1e79d10e 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -134,7 +134,7 @@ 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