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[34.83.92.57]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-6f4d2ade2c9sm11332969b3a.125.2024.05.15.10.44.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 May 2024 10:44:47 -0700 (PDT) Date: Wed, 15 May 2024 17:44:44 +0000 From: Carlos Llamas To: Yenchia Chen Cc: stable@vger.kernel.org, Eric Dumazet , Jakub Kicinski , "David S. Miller" , Matthias Brugger , Sasha Levin , Simon Horman , Ryosuke Yasuoka , Zhengchao Shao , Pedro Tammela , Thomas Graf , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH 5.15 1/2] netlink: annotate lockless accesses to nlk->max_recvmsg_len Message-ID: References: <20240515073644.32503-1-yenchia.chen@mediatek.com> <20240515073644.32503-2-yenchia.chen@mediatek.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240515073644.32503-2-yenchia.chen@mediatek.com> On Wed, May 15, 2024 at 03:36:37PM +0800, Yenchia Chen wrote: > From: Eric Dumazet > > syzbot reported a data-race in data-race in netlink_recvmsg() [1] > > Indeed, netlink_recvmsg() can be run concurrently, > and netlink_dump() also needs protection. > > [1] > BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg > > read to 0xffff888141840b38 of 8 bytes by task 23057 on cpu 0: > netlink_recvmsg+0xea/0x730 net/netlink/af_netlink.c:1988 > sock_recvmsg_nosec net/socket.c:1017 [inline] > sock_recvmsg net/socket.c:1038 [inline] > __sys_recvfrom+0x1ee/0x2e0 net/socket.c:2194 > __do_sys_recvfrom net/socket.c:2212 [inline] > __se_sys_recvfrom net/socket.c:2208 [inline] > __x64_sys_recvfrom+0x78/0x90 net/socket.c:2208 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > write to 0xffff888141840b38 of 8 bytes by task 23037 on cpu 1: > netlink_recvmsg+0x114/0x730 net/netlink/af_netlink.c:1989 > sock_recvmsg_nosec net/socket.c:1017 [inline] > sock_recvmsg net/socket.c:1038 [inline] > ____sys_recvmsg+0x156/0x310 net/socket.c:2720 > ___sys_recvmsg net/socket.c:2762 [inline] > do_recvmmsg+0x2e5/0x710 net/socket.c:2856 > __sys_recvmmsg net/socket.c:2935 [inline] > __do_sys_recvmmsg net/socket.c:2958 [inline] > __se_sys_recvmmsg net/socket.c:2951 [inline] > __x64_sys_recvmmsg+0xe2/0x160 net/socket.c:2951 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > value changed: 0x0000000000000000 -> 0x0000000000001000 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 23037 Comm: syz-executor.2 Not tainted 6.3.0-rc4-syzkaller-00195-g5a57b48fdfcb #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 > > Fixes: 9063e21fb026 ("netlink: autosize skb lengthes") > Reported-by: syzbot > Signed-off-by: Eric Dumazet > Reviewed-by: Simon Horman > Link: https://lore.kernel.org/r/20230403214643.768555-1-edumazet@google.com > Signed-off-by: Jakub Kicinski > Signed-off-by: yenchia.chen > --- The conflict resolution looks good to me, thanks! Reviewed-by: Carlos Llamas