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AJvYcCXELhAErsHmqN0Ybhp3zqK21qEdSuj87gwZKvTZoU0K/RK8b3yYSmGxyO25//I1MV5Qk/rJPrU=@vger.kernel.org X-Gm-Message-State: AOJu0YxnSWQ6rhcHB4yJQuC/P6adMKXDvBfciHf4VCFEa3bf2UA64LqC eEaPnEOO7U9g8W0HklQmKKtmgnAM+6o5Pq7WtLEwCoV8Gfwz9h2dBm1wZx0gx1lkLfiXpUcfJj3 06tNRJAdKs6wIMDN5ouS7zi4VOS7VhVJldWlfqG3TJmWC07tbXinD7N4= X-Google-Smtp-Source: AGHT+IE/31vwbeN8/st/bA6EdwxIedVRyFYVoRTUS4oPAEtJSt+EjwddvATfW7/KCH2jCSP+q4pEa21n+YN0U2/NcPq+Taso1onA Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:98:b0:3ce:7fc3:9f76 with SMTP id e9e14a558f8ab-3cffe3e527cmr168094655ab.6.1738533678463; Sun, 02 Feb 2025 14:01:18 -0800 (PST) Date: Sun, 02 Feb 2025 14:01:18 -0800 In-Reply-To: <000000000000a7fb55061ce6cc5a@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <679feb2e.050a0220.d7c5a.0078.GAE@google.com> Subject: Re: [syzbot] [net?] possible deadlock in do_ipv6_setsockopt (4) From: syzbot To: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: c2933b2befe2 Merge tag 'net-6.14-rc1' of git://git.kernel... git tree: net-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=12a22eb0580000 kernel config: https://syzkaller.appspot.com/x/.config?x=d033b14aeef39158 dashboard link: https://syzkaller.appspot.com/bug?extid=3433b5cb8b2b70933f8d compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12896d18580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12c69724580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/c7667ae12603/disk-c2933b2b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/944ca63002c1/vmlinux-c2933b2b.xz kernel image: https://storage.googleapis.com/syzbot-assets/30748115bf0b/bzImage-c2933b2b.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+3433b5cb8b2b70933f8d@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 6.13.0-syzkaller-09685-gc2933b2befe2 #0 Not tainted ------------------------------------------------------ syz-executor323/5834 is trying to acquire lock: ffff8880352e2cd8 (sk_lock-AF_INET6){+.+.}-{0:0}, at: do_ipv6_setsockopt+0xbf7/0x3640 net/ipv6/ipv6_sockglue.c:567 but task is already holding lock: ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: do_ipv6_setsockopt+0x9e8/0x3640 net/ipv6/ipv6_sockglue.c:566 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rtnl_mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 smc_vlan_by_tcpsk+0x399/0x4e0 net/smc/smc_core.c:1908 __smc_connect+0x296/0x1910 net/smc/af_smc.c:1520 smc_connect+0x868/0xde0 net/smc/af_smc.c:1696 __sys_connect_file net/socket.c:2040 [inline] __sys_connect+0x288/0x2d0 net/socket.c:2059 __do_sys_connect net/socket.c:2065 [inline] __se_sys_connect net/socket.c:2062 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2062 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sk_lock-AF_INET6){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 lock_sock_nested+0x48/0x100 net/core/sock.c:3645 do_ipv6_setsockopt+0xbf7/0x3640 net/ipv6/ipv6_sockglue.c:567 ipv6_setsockopt+0x5d/0x170 net/ipv6/ipv6_sockglue.c:993 do_sock_setsockopt+0x3af/0x720 net/socket.c:2298 __sys_setsockopt net/socket.c:2323 [inline] __do_sys_setsockopt net/socket.c:2329 [inline] __se_sys_setsockopt net/socket.c:2326 [inline] __x64_sys_setsockopt+0x1ee/0x280 net/socket.c:2326 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET6); lock(rtnl_mutex); lock(sk_lock-AF_INET6); *** DEADLOCK *** 1 lock held by syz-executor323/5834: #0: ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: do_ipv6_setsockopt+0x9e8/0x3640 net/ipv6/ipv6_sockglue.c:566 stack backtrace: CPU: 0 UID: 0 PID: 5834 Comm: syz-executor323 Not tainted 6.13.0-syzkaller-09685-gc2933b2befe2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208 check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 lock_sock_nested+0x48/0x100 net/core/sock.c:3645 do_ipv6_setsockopt+0xbf7/0x3640 net/ipv6/ipv6_sockglue.c:567 ipv6_setsockopt+0x5d/0x170 net/ipv6/ipv6_sockglue.c:993 do_sock_setsockopt+0x3af/0x720 net/socket.c:2298 __sys_setsockopt net/socket.c:2323 [inline] __do_sys_setsockopt net/socket.c:2329 [inline] __se_sys_setsockopt net/socket.c:2326 [inline] __x64_sys_setsockopt+0x1ee/0x280 net/socket.c:2326 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5f02247369 Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe9a248bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007ffe9a248da8 RCX: 00007f5f02247369 RDX: 000000000000001b RSI: 0000000000000029 RDI: 0000000000000004 RBP: 00007f5f022ba610 R08: 0000000000000000 R09: 00007ffe9a248da8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffe9a248d98 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.