From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 2E8F9173 for ; Sun, 20 Aug 2023 00:08:22 +0000 (UTC) Received: from mail-pf1-x430.google.com (mail-pf1-x430.google.com [IPv6:2607:f8b0:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AAC9B10554B; Sat, 19 Aug 2023 11:08:35 -0700 (PDT) Received: by mail-pf1-x430.google.com with SMTP id d2e1a72fcca58-68a3e271491so27598b3a.0; Sat, 19 Aug 2023 11:08:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692468515; x=1693073315; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=lV81kcD9vzqzEmQhBftWFfOiwm9XqB0HTp7lUGKFHuQ=; b=C7qYTo1LyPFHC2dm+MmwF+hLNzvcmrZB2LBFsnfNl1z0tB0EgpgsWyN3xsA2TJHxV2 iIsZr7PvOShCd4TbXPkvfAPkRZ0XWp+JrNo5O07S5xk95uw+vQK9PMCVopfoztX6hX/G RYtUfseiGEDIWpMAmgxkvAx9ESZCq+t/sNbF3YEQPjBA6IGdJEJKq6LOQfpsI2lVxv5L X25Fa/6NlHP9i5M/3MUiRiW8Oj+JDL22S3cfRyz6G3S/FyWnK+pp8WyCO3IKTDsyfxkx FtwFt4bYyQDv3apQyaJJHRIt+cM6/fK0AoXmay7m3uqFsdn7SFdmg/vK5Ry4uo9uhrX2 K+Rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692468515; x=1693073315; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=lV81kcD9vzqzEmQhBftWFfOiwm9XqB0HTp7lUGKFHuQ=; b=CJ6VK5Wb9/XrK+lMpokHqwpqqRJeuoIz6p+M9bMH7KHIgHb+tVVY5mgNZhcCIXayRU KHQxIk2WGMbk3e1rhPvTYpybpRILLhm+yZfboTkKG6uA5aCdimetbYpiPyWMnV/r83hg XzNyXqxFs2/HKTHiZVSCKNb2WZEJZW9Ufkp4Rb1y4M+WOlmzdcGIqe86USKMf4a1j2X+ 6EuQbVdkopzjLY8NLH0B1AOq8AvVudy2FnP25O7OKHqUkqp7Hh99uX8AX015t4JQwHFi qG9seP7WjMfQCB4NzxeW9Gi6lYY9uApOqIliAA6T4TfGVT6A+w1veeYuHO1T4wzJe6og g+fQ== X-Gm-Message-State: AOJu0YxIfGeXCQCQSfHsc1Pdr0Kpf0/aW0J1HijZ/rL+Ji7AXLYnXkVx UbC4EryKpYVaU7PSqksEDk0= X-Google-Smtp-Source: AGHT+IF7EedqvwbI3ba5+mmLhdYeO7tD4JUyYmKEOPCFp8pBzMa7oyrnaLm3L04xO1eVykt07TWdOA== X-Received: by 2002:a05:6a20:1447:b0:148:40cf:b832 with SMTP id a7-20020a056a20144700b0014840cfb832mr2009601pzi.18.1692468515010; Sat, 19 Aug 2023 11:08:35 -0700 (PDT) Received: from DESKTOP-7B1REV8.localdomain ([2001:569:5755:c600:f49d:4018:e752:1f22]) by smtp.gmail.com with ESMTPSA id t16-20020a170902e85000b001b8b07bc600sm3890891plg.186.2023.08.19.11.08.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Aug 2023 11:08:34 -0700 (PDT) From: Qingjie Xing To: edumazet@google.com Cc: davem@davemloft.net, dhowells@redhat.com, fw@strlen.de, johannes@sipsolutions.net, keescook@chromium.org, kuba@kernel.org, kuniyu@amazon.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, pctammela@mojatatu.com, xqjcool@gmail.com Subject: Re: [PATCH] netlink: Fix the netlink socket malfunction due to concurrency Date: Sat, 19 Aug 2023 11:04:48 -0700 Message-Id: <20230819180448.2315-1-xqjcool@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net This piece of code has been present since the Linux code v2.6.12 was incorporated into Git management. I believe this modification could potentially address the concurrent issue we've been discussing. In netlink_rcv_wake(), as described in [2], the socket's receive queue is empty, indicated by sk_rmem_alloc being 0. At this point, concurrent netlink_attachskb() calls netlink_overrun(). In this critical state, the sk_rmem_alloc of the socket will not instantly transition from 0 to a value greater than sk_rcvbuf.