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 B9BBBECAAD3 for ; Tue, 30 Aug 2022 02:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229869AbiH3CeC (ORCPT ); Mon, 29 Aug 2022 22:34:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229716AbiH3CeB (ORCPT ); Mon, 29 Aug 2022 22:34:01 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F42A9E2D9 for ; Mon, 29 Aug 2022 19:34:01 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id q9so9402525pgq.6 for ; Mon, 29 Aug 2022 19:34:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc; bh=NC5D4/9ODNR2utpR0eH1iQpIrCsga7h77tOJJBtfqvs=; b=jPn0Ejz+gQCyY2cBc+ze45WRDr3MJCFQPEjts9JdS0WiPA2OcXwifpzBQdlw+rlGbc UhnOQHZTGDooAuLvEJ2XKX/++OPABkaBR0cwH2kHib+D/hvS520pen9S8NhkwHYweLEO rL8SSW3qp9NFGTkn6CWJwMwe6/ZnoTzCXc5xQ+NnhpbQnBbXHbXSKKmEIJCWvxLAc308 i905uvMvQFax5KdAIiLQPTlmFZlzbalkophLk9AObwU2WOG8MKwFNJfiAOz6rYtJsX0Q Fsc/QGZ/KfB7rsO/ggrBV4pwgrQIg3Otn17eOPsRSbSr/cttkrDfl7vxeEnWasKQkcmG jHQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-message-state:from:to :cc; bh=NC5D4/9ODNR2utpR0eH1iQpIrCsga7h77tOJJBtfqvs=; b=FYzMlkYoSpxCsDNa6vAyYrjpoTfjXWy2b9vxrIoazkaWPK0jIOWU9jqJjg9V2h/3gY MuSb9r0sFuAnpjRFNt8LRltIkG+r1aRJMi/AJhrK/kq9H0bQUF63q/yS02v4mAGvhVkd D+on8Lfy5pNTIyp+kdwm3axgacYFXFctN662cJhhL6jdms4HWp1vjL/tOU2hANgZjlQA H4otasoI9U+5I4NJ4TsqzxJ8UOZi3oh3TaNo4gT39+ASX9Mqt+uTmEkkR17KKyEjH+2S NT1Vc5YWbLM7ftd9bO+CAycIa3s42tQjxJe7a2ORaTC6Sx2NvELndda9zsHolYy1LCIg ScyQ== X-Gm-Message-State: ACgBeo0Szro8QfieyOU2kPYPyUxUGccnVXgI9MqXFpqY0DStobZRBLfq vdiQpAZGdZ5kJvuMV3+7g8Y= X-Google-Smtp-Source: AA6agR5IHa+ebY/xTobkfDq3rnoYqvazJEyw/BkkM5rveXjfWsh1SahAXF4oErmJ+iDuKuBKZlvSqw== X-Received: by 2002:a05:6a00:a90:b0:530:2f3c:da43 with SMTP id b16-20020a056a000a9000b005302f3cda43mr19287984pfl.50.1661826840486; Mon, 29 Aug 2022 19:34:00 -0700 (PDT) Received: from localhost ([98.97.36.213]) by smtp.gmail.com with ESMTPSA id s3-20020a170902ea0300b00174c5fb500dsm3264442plg.116.2022.08.29.19.33.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Aug 2022 19:33:59 -0700 (PDT) Date: Mon, 29 Aug 2022 19:33:55 -0700 From: John Fastabend To: Liu Jian , john.fastabend@gmail.com, jakub@cloudflare.com, edumazet@google.com, davem@davemloft.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com, andrii@kernel.org, mykolal@fb.com, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, bpf@vger.kernel.org Cc: liujian56@huawei.com Message-ID: <630d77139b34c_9c0be2089d@john.notmuch> In-Reply-To: <20220823133755.314697-2-liujian56@huawei.com> References: <20220823133755.314697-1-liujian56@huawei.com> <20220823133755.314697-2-liujian56@huawei.com> Subject: RE: [PATCH bpf-next v2 1/2] net: If the sock is dead, do not access sock's sk_wq in sk_stream_wait_memory Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Liu Jian wrote: > Fix the below NULL pointer dereference: > > [ 14.471200] Call Trace: > [ 14.471562] > [ 14.471882] lock_acquire+0x245/0x2e0 > [ 14.472416] ? remove_wait_queue+0x12/0x50 > [ 14.473014] ? _raw_spin_lock_irqsave+0x17/0x50 > [ 14.473681] _raw_spin_lock_irqsave+0x3d/0x50 > [ 14.474318] ? remove_wait_queue+0x12/0x50 > [ 14.474907] remove_wait_queue+0x12/0x50 > [ 14.475480] sk_stream_wait_memory+0x20d/0x340 > [ 14.476127] ? do_wait_intr_irq+0x80/0x80 > [ 14.476704] do_tcp_sendpages+0x287/0x600 > [ 14.477283] tcp_bpf_push+0xab/0x260 > [ 14.477817] tcp_bpf_sendmsg_redir+0x297/0x500 > [ 14.478461] ? __local_bh_enable_ip+0x77/0xe0 > [ 14.479096] tcp_bpf_send_verdict+0x105/0x470 > [ 14.479729] tcp_bpf_sendmsg+0x318/0x4f0 > [ 14.480311] sock_sendmsg+0x2d/0x40 > [ 14.480822] ____sys_sendmsg+0x1b4/0x1c0 > [ 14.481390] ? copy_msghdr_from_user+0x62/0x80 > [ 14.482048] ___sys_sendmsg+0x78/0xb0 > [ 14.482580] ? vmf_insert_pfn_prot+0x91/0x150 > [ 14.483215] ? __do_fault+0x2a/0x1a0 > [ 14.483738] ? do_fault+0x15e/0x5d0 > [ 14.484246] ? __handle_mm_fault+0x56b/0x1040 > [ 14.484874] ? lock_is_held_type+0xdf/0x130 > [ 14.485474] ? find_held_lock+0x2d/0x90 > [ 14.486046] ? __sys_sendmsg+0x41/0x70 > [ 14.486587] __sys_sendmsg+0x41/0x70 > [ 14.487105] ? intel_pmu_drain_pebs_core+0x350/0x350 > [ 14.487822] do_syscall_64+0x34/0x80 > [ 14.488345] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > The test scene as following flow: > thread1 thread2 > ----------- --------------- > tcp_bpf_sendmsg > tcp_bpf_send_verdict > tcp_bpf_sendmsg_redir sock_close > tcp_bpf_push_locked __sock_release > tcp_bpf_push //inet_release > do_tcp_sendpages sock->ops->release > sk_stream_wait_memory // tcp_close > sk_wait_event sk->sk_prot->close > release_sock(__sk); > *** > > lock_sock(sk); > __tcp_close > sock_orphan(sk) > sk->sk_wq = NULL > release_sock > **** > lock_sock(__sk); > remove_wait_queue(sk_sleep(sk), &wait); > sk_sleep(sk) > //NULL pointer dereference > &rcu_dereference_raw(sk->sk_wq)->wait > > While waiting for memory in thread1, the socket is released with its wait > queue because thread2 has closed it. This caused by tcp_bpf_send_verdict > didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1. > > We should check if SOCK_DEAD flag is set on wakeup in > sk_stream_wait_memory, before accessing the wait queue. > > Suggested-by: Jakub Sitnicki > Signed-off-by: Liu Jian > --- This LGTM but would be great if Eric could ACK as well from TCP side. Acked-by: John Fastabend