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 EFA9C367 for ; Sat, 19 Aug 2023 22:40:14 +0000 (UTC) Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61CA71FB86B; Sat, 19 Aug 2023 11:28:05 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id d2e1a72fcca58-6887c3aac15so1860233b3a.2; Sat, 19 Aug 2023 11:28:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692469685; x=1693074485; 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=VYLM6eGJKRGVhn2Ekxvmmk/IxAN5ZqHbANxjoPuznd3ND4PNVXNbtT8ZOexZ9dcdIs l5NK7l8KaLF2I0LZ/oFlo9HP3KbdO4MBVwxU5SQk/yrGHsXxm1VJsqpYd2fDYj1RRidV grAW5a+GIMdE6PwljrNcNYrfPGEWa+vFYXr9sn0v8TJVb8xakHlcH433M5AjsyFRHXap bg+ZoGJHqoPiuUwhTaWfgEC2wNNvS1mAJdEaj5Wo8Z+nOd42uZFqykKZFoaOGoD1XBYy /txmBbFuxzLT/FYePrjUEIbnN1jyALIGgAvaKnCFUsuHThsANFW6qGDkwFf9LTAWBpQz BXhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692469685; x=1693074485; 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=lKQiys9uf2G2N3it4N1FeMtnZpm2nf5QlqoSc3Nnrs48HPRIbopxp9H6iD2Dxos4D3 UexDA7tG4o/4mIPJplpclPtj+I46QHDeMCiUBURLuxuXdS/6Qgg8S3BJC3oOPEIeMHlL 7gqYVshupMyvgRlB6CAkElABr+hgAiQZ18L7bnicOPED1dZw5yRy+oznxDONREoEG+VO GBiLUDYszP+UW380E/XLLi8V94J7xD+ly9m38FDWAT/nbZvXi/JKL6QxuIC7LKQrAR2b jGmmfgWppT6BxjXahBGWGgnTLme+ADSfRGrrBqdPjfgh4UQRwT6xvgShmA+o2sscap7+ y3pg== X-Gm-Message-State: AOJu0YzeYyrfJE5iKRFl0heaJoR5JPYr8rqFM9it8IwjK5Sv5Xfn8hVA MNNgklYjOK9OM4OI42+/jtE= X-Google-Smtp-Source: AGHT+IEmPsxqkWPlrcjuJvptns5x3p1VIrYcf/FJ+r5YwMaev10rG6h9Gg+q8okY9eKsmQQudhk9FA== X-Received: by 2002:a05:6a20:548f:b0:143:4382:f836 with SMTP id i15-20020a056a20548f00b001434382f836mr3155486pzk.14.1692469684798; Sat, 19 Aug 2023 11:28:04 -0700 (PDT) Received: from DESKTOP-7B1REV8.localdomain ([2001:569:5755:c600:f49d:4018:e752:1f22]) by smtp.gmail.com with ESMTPSA id e4-20020aa78c44000000b00682af93093dsm3464266pfd.45.2023.08.19.11.28.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Aug 2023 11:28:04 -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 11:24:36 -0700 Message-Id: <20230819182436.2369-1-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_NONE,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.