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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E3ECC0015E for ; Fri, 21 Jul 2023 19:12:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231861AbjGUTMK (ORCPT ); Fri, 21 Jul 2023 15:12:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231859AbjGUTMJ (ORCPT ); Fri, 21 Jul 2023 15:12:09 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C71FAE4C for ; Fri, 21 Jul 2023 12:12:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5C14061D76 for ; Fri, 21 Jul 2023 19:12:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EF52C433C9; Fri, 21 Jul 2023 19:12:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689966727; bh=M+m7MiydM2ia4HSXZj21M/dC1iZRWupB58WripmwcL4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ou8tvHNzpiCLR9aknctM95iuAE44Slh1OnkLfd59e8oUmJ5Ct1jSo1aZrPxJ3gFfM faIb8ToqzpLpOkM3TlC/FpGLIzEj4zqRou74Noz+kc4OHf/NIhHMqyb57sebsOGRl4 tKbCYYW6cHBn/Ovbw65d1PHXUP6MLUzk9MxoBeq0= 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 5.15 439/532] net/sched: make psched_mtu() RTNL-less safe Date: Fri, 21 Jul 2023 18:05:43 +0200 Message-ID: <20230721160638.374585958@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160614.695323302@linuxfoundation.org> References: <20230721160614.695323302@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 9cd2d4e84913f..d0d9dd2483dd3 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -141,7 +141,7 @@ 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