From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f206.google.com (mail-il1-f206.google.com [209.85.166.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 68D6326BDAE for ; Tue, 11 Feb 2025 02:23:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739240610; cv=none; b=WJP8B8MFHMfsvt7oRYWSuATueIetzN6XiD8JZZISdr/cqTLptzs3vt5GDojnnjQaYofC+AlNpyNcgLBFipRkAbgJ7l8NnvGjjqaqDTmf823m2gFPVNSOiwYNSX2FMgFVrHbSVQ5JCsxn/XF8c4e6JMNloiqbkIjvyeObDRRAEjg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739240610; c=relaxed/simple; bh=Zr1/YMrRfSKpbMAcCv8l2Ccd7c0b9BRBwRhG+O1JcRY=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=giJ0fwzv4PIaqIelArTS7FF0gkthr8iLjidSGgLsZS4YfN5eZwHqT4OUDFNj1Sr809lVuuz2dszxH/Rxr4ftgin9NnBrWHl9qA6USFDOREKUnc9uvty7nigW4/78qYBbRXVfBUTEEbYM5/LXFQgB6u5Cx/VmeWEXw8/3dhzlO68= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.206 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-il1-f206.google.com with SMTP id e9e14a558f8ab-3d158477b5fso13955145ab.0 for ; Mon, 10 Feb 2025 18:23:28 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739240607; x=1739845407; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=166LBbt64jZ5pcV15fCq8VCvbhMSg2uka6qoDR9pF6Y=; b=VMnxweqFUXtcQlw1YrUu3rmJN2YwQgiPvjaMQoDUSFHRK+cTDRfCP6WmxR7TLD/h6X qyIYK7RAJL/p+Ejsg72eVqDRAP2oQTQPk3+jhfwkbRjrZrg70vFnkex/9cCwIojz48nX mPdR5iLWC4du4f0Kq6V+TFwexV9twg4yWnpqvwA83hXtTA4vjVL6DVF5qYJxe1FJ2BKp UNYyPq7H+jpcsX+r4b2iXjlMlBZ3h+GwynG423lS8wvIDdQD2yg47MBCikhe5K0bbCrB vgH6RhZCd5XEqZt394D0By7LzQlY6G1kyVRcDBsJO2Dg5sWLduNYuhY3lAzxj2hqMI+l RPPA== X-Forwarded-Encrypted: i=1; AJvYcCVaVp4c2qUOMtL2iXA2WjIAfS90Y7SDgkxr59PqZHS8TMC8WQo8m9Nom8sFgQEQd+DhT2wbzq0En/3X@vger.kernel.org X-Gm-Message-State: AOJu0Yx/AqmZW9hUZNu1160x6aDtQBEfeldeBxvJfrb8pQ+LPWlCpiYf R3kjb4buB8xnrX1BDpR+nd1WmYDLg4nuxLG4H9pO8708T3H15IkSnF6RGYIoSvfexTMPBCoTeW3 4TMswUe7l/9Pv/lRpqW7tWRfdNMKjv6LIEVzDnJCojvRXQ8vpBLIJqT0= X-Google-Smtp-Source: AGHT+IHaBPniZelBTlU5baRXYIYMNUjG3TGM8YvVe+IrDitGwDSK2DfuJxQ+7eMeFKYFdnKSW+jc2vQN4mkXPnjJaei0YrERueLY Precedence: bulk X-Mailing-List: linux-hams@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:2142:b0:3d0:4b3d:75ba with SMTP id e9e14a558f8ab-3d13dcee89amr117673305ab.4.1739240607441; Mon, 10 Feb 2025 18:23:27 -0800 (PST) Date: Mon, 10 Feb 2025 18:23:27 -0800 In-Reply-To: <0000000000001abfb506221890b2@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <67aab49f.050a0220.110943.0038.GAE@google.com> Subject: Re: [syzbot] [hams?] possible deadlock in nr_rt_device_down (3) From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, kuba@kernel.org, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, ralf@linux-mips.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 34c84b394890 Merge branch 'netconsole-cpu-population' git tree: net-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=10a4fb18580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1909f2f0d8e641ce dashboard link: https://syzkaller.appspot.com/bug?extid=ccdfb85a561b973219c7 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=15d372a4580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14e8c3f8580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a387ecc01ea6/disk-34c84b39.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/25869f4f9e04/vmlinux-34c84b39.xz kernel image: https://storage.googleapis.com/syzbot-assets/bfdfecda0154/bzImage-34c84b39.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ccdfb85a561b973219c7@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 6.14.0-rc1-syzkaller-00206-g34c84b394890 #0 Not tainted ------------------------------------------------------ syz-executor309/5900 is trying to acquire lock: ffffffff8fe14a38 (nr_node_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff8fe14a38 (nr_node_list_lock){+...}-{3:3}, at: nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517 but task is already holding lock: ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_device_down+0x28/0x7b0 net/netrom/nr_route.c:514 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (nr_neigh_list_lock){+...}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_remove_neigh net/netrom/nr_route.c:307 [inline] nr_dec_obs net/netrom/nr_route.c:472 [inline] nr_rt_ioctl+0x398/0xfb0 net/netrom/nr_route.c:692 sock_do_ioctl+0x158/0x460 net/socket.c:1194 sock_ioctl+0x626/0x8e0 net/socket.c:1313 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 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 -> #1 (&nr_node->node_lock){+...}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_node_lock include/net/netrom.h:152 [inline] nr_dec_obs net/netrom/nr_route.c:459 [inline] nr_rt_ioctl+0x192/0xfb0 net/netrom/nr_route.c:692 sock_do_ioctl+0x158/0x460 net/socket.c:1194 sock_ioctl+0x626/0x8e0 net/socket.c:1313 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 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 (nr_node_list_lock){+...}-{3:3}: 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 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517 nr_device_event+0x134/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9257 dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:563 dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826 sock_do_ioctl+0x240/0x460 net/socket.c:1208 sock_ioctl+0x626/0x8e0 net/socket.c:1313 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 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: Chain exists of: nr_node_list_lock --> &nr_node->node_lock --> nr_neigh_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(nr_neigh_list_lock); lock(&nr_node->node_lock); lock(nr_neigh_list_lock); lock(nr_node_list_lock); *** DEADLOCK *** 2 locks held by syz-executor309/5900: #0: ffffffff8fcc0108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fcc0108 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x706/0x1340 net/core/dev_ioctl.c:825 #1: ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_device_down+0x28/0x7b0 net/netrom/nr_route.c:514 stack backtrace: CPU: 1 UID: 0 PID: 5900 Comm: syz-executor309 Not tainted 6.14.0-rc1-syzkaller-00206-g34c84b394890 #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 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517 nr_device_event+0x134/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9257 dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:563 dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826 sock_do_ioctl+0x240/0x460 net/socket.c:1208 sock_ioctl+0x626/0x8e0 net/socket.c:1313 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 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: 0033:0x7f052c137829 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 1a 00 00 90 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:00007ffcc38957c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f052c137829 RDX: 0000400000000000 RSI: 0000000000008914 RDI: 0000000000000007 RBP: 0000000000000000 R08: 00007f052c185214 R09: 00007f052c185214 R10: fffffffffffffe1d R11: 0000000000000246 R12: 00007f052c1854a8 R13: 00007f052c185084 R14: 00007ffcc3895800 R15: 0000000000000000 --- 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.