From patchwork Fri Jul 29 11:00:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hangyu Hua X-Patchwork-Id: 12932349 X-Patchwork-Delegate: kuba@kernel.org 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 0D6B1C00144 for ; Fri, 29 Jul 2022 11:00:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235402AbiG2LAn (ORCPT ); Fri, 29 Jul 2022 07:00:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234639AbiG2LAm (ORCPT ); Fri, 29 Jul 2022 07:00:42 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B41102A408; Fri, 29 Jul 2022 04:00:40 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id k79so100675pfd.8; Fri, 29 Jul 2022 04:00:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc; bh=+/iPCd/Fzs9lGqRmUEuLJiLQfcVAsWgZMz3tPz5hhRQ=; b=MHjjq2LT4+2Lau6NVZpwhf+0AWyWdR3H0vDiDs5DI2gcp1Na9tGHe1Tw0A9ViBHDXA PS+V7i3Y3M5fER+mEqpzZu4ReChmqYPMzQ1+geknjkpXjnbxhNTkmiGp7SZZUoui8/SX eRuITytkPVXC1DXYw6mEkAXE4tXgc9aPYEkleZh2aE21bmSDrvLNPsW6zhSc6kmjdyrY MKYHi1WAnAF3p73oEncEY7g1FtkkvTyFL4PvWlrA6LbvXoJL1S4h/gBPUsmhr6BNhpPB 8Dc0IZO/6lHkj/IYSMkanvuSYRNQ3vBEf8IiphFoYxMPZTvBCcrUCTQfqkh8JuV26A8T Jp5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc; bh=+/iPCd/Fzs9lGqRmUEuLJiLQfcVAsWgZMz3tPz5hhRQ=; b=qlZhBHbAxLYdqlY9DtNGtaRsXE1J2zCAe78ndKLiVgEMloNL+Xnq4VrZqpT+Fqaxs2 yIBkJMfk1mJl3CQv4zMRXwpMi5VyGlT10cM6UWcjEZfzXBPpddbVNf8OwNlY/OzRsvz5 QbK20OQC247Uz7RDx1/DAPRJXt5rnsit1eIJ53ptLVHm4ZR3nENHojFtc45IJQfYsH9J QRaMn429YDZbl2MiSq+hoZc8YQq4hEB7HiE1Pfl8Ej+Z9NPZApGM8uamzPHCBAAEK+2U V91Skd4P63Awc7tA8K9mxuVe750RZ8+Ael3lPcq7ycZmVK/WddADM1K1bB/6lh0s8Hkh +k5Q== X-Gm-Message-State: AJIora/XmYwZeFAkZ8Fjx7wGuSqw0cD7QGDmRTj+yY8ZYjlrH9lwQ9Ka bIFm2YY5TTwK7kNpygf0agI= X-Google-Smtp-Source: AGRyM1tEhNVtRjJtquaYNWRwmabmY/N9Fcuj5cMr0H+F/vXVpXqWTNRTC801SAun88tZtNfOW2Vtmw== X-Received: by 2002:a65:6398:0:b0:415:7d00:c1de with SMTP id h24-20020a656398000000b004157d00c1demr2546776pgv.610.1659092440239; Fri, 29 Jul 2022 04:00:40 -0700 (PDT) Received: from localhost.localdomain ([129.227.148.126]) by smtp.gmail.com with ESMTPSA id l1-20020a170902ec0100b0016d338160d6sm3201118pld.155.2022.07.29.04.00.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Jul 2022 04:00:39 -0700 (PDT) From: Hangyu Hua To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, kuniyu@amazon.co.jp, joannelkoong@gmail.com, richard_siegfried@systemli.org, socketcan@hartkopp.net, ian.mcdonald@jandi.co.nz, acme@mandriva.com, gerrit@erg.abdn.ac.uk Cc: dccp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Hangyu Hua Subject: [PATCH v2] dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock Date: Fri, 29 Jul 2022 19:00:27 +0800 Message-Id: <20220729110027.40569-1-hbh25y@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org In the case of sk->dccps_qpolicy == DCCPQ_POLICY_PRIO, dccp_qpolicy_full will drop a skb when qpolicy is full. And the lock in dccp_sendmsg is released before sock_alloc_send_skb and then relocked after sock_alloc_send_skb. The following conditions may lead dccp_qpolicy_push to add skb to an already full sk_write_queue: thread1--->lock thread1--->dccp_qpolicy_full: queue is full. drop a skb thread1--->unlock thread2--->lock thread2--->dccp_qpolicy_full: queue is not full. no need to drop. thread2--->unlock thread1--->lock thread1--->dccp_qpolicy_push: add a skb. queue is full. thread1--->unlock thread2--->lock thread2--->dccp_qpolicy_push: add a skb! thread2--->unlock Fix this by moving dccp_qpolicy_full. Fixes: b1308dc015eb ("[DCCP]: Set TX Queue Length Bounds via Sysctl") Signed-off-by: Hangyu Hua --- v2: 1. call dccp_qpolicy_full first after relocking. 2. change "Fixes:" tag. net/dccp/proto.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/dccp/proto.c b/net/dccp/proto.c index eb8e128e43e8..e13641c65f88 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -736,11 +736,6 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) lock_sock(sk); - if (dccp_qpolicy_full(sk)) { - rc = -EAGAIN; - goto out_release; - } - timeo = sock_sndtimeo(sk, noblock); /* @@ -759,6 +754,11 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (skb == NULL) goto out_release; + if (dccp_qpolicy_full(sk)) { + rc = -EAGAIN; + goto out_discard; + } + if (sk->sk_state == DCCP_CLOSED) { rc = -ENOTCONN; goto out_discard;