From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f207.google.com (mail-il1-f207.google.com [209.85.166.207]) (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 8C59C2E54BC for ; Thu, 26 Jun 2025 13:33:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750944813; cv=none; b=A2WOePXtbEh1mFLhN6X2E29iBaq5mSebi3uWwvDAhI60b3LB+/vBdYdIvhMcjDNqw2NA38MgvOpJtWjvOumRziPM4IrsGA6+c33mUGIX3H7+otm/ujZvdsweeQiBaOyt2xxooeDXpGfwxz4qL1eiwKYvxBs/riHvxO+aXQlOtuQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750944813; c=relaxed/simple; bh=v01uEnPZNFuwIhQpYvDDHT0RyQYE6ARQrYMccQw3PeU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:248a:b0:3dd:ce9b:aa17 with SMTP id e9e14a558f8ab-3df3292bebfmr99052815ab.20.1750944810724; Thu, 26 Jun 2025 06:33:30 -0700 (PDT) Date: Thu, 26 Jun 2025 06:33:30 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <685d4c2a.a00a0220.2e5631.028c.GAE@google.com> Subject: [syzbot] [hams?] possible deadlock in nr_rt_ioctl (2) 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, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 09a0fa92e5b4 Merge tag 'selinux-pr-20250107' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=122714b0580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7bdfbaac3fbb90d6 dashboard link: https://syzkaller.appspot.com/bug?extid=14afda08dc3484d5db82 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b8db0f980000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-09a0fa92.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/38215ac79538/vmlinux-09a0fa92.xz kernel image: https://storage.googleapis.com/syzbot-assets/117da94a1c81/bzImage-09a0fa92.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+14afda08dc3484d5db82@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc6-syzkaller-00038-g09a0fa92e5b4 #0 Not tainted ------------------------------------------------------ syz.3.32/6172 is trying to acquire lock: ffffffff9012a4f8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff9012a4f8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_remove_neigh net/netrom/nr_route.c:307 [inline] ffffffff9012a4f8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_del_node net/netrom/nr_route.c:342 [inline] ffffffff9012a4f8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_ioctl+0x207f/0x29e0 net/netrom/nr_route.c:678 but task is already holding lock: ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: nr_del_node net/netrom/nr_route.c:335 [inline] ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: nr_rt_ioctl+0x2aa/0x29e0 net/netrom/nr_route.c:678 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&nr_node->node_lock){+...}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_node_lock include/net/netrom.h:152 [inline] nr_rt_device_down+0x188/0x7f0 net/netrom/nr_route.c:519 nr_device_event+0x126/0x170 net/netrom/af_netrom.c:126 notifier_call_chain+0xb7/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1996 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline] call_netdevice_notifiers net/core/dev.c:2048 [inline] __dev_notify_flags+0x1f9/0x2e0 net/core/dev.c:8992 dev_change_flags+0x10c/0x160 net/core/dev.c:9028 dev_ifsioc+0x9c8/0x10b0 net/core/dev_ioctl.c:526 dev_ioctl+0x224/0x10c0 net/core/dev_ioctl.c:783 sock_do_ioctl+0x19e/0x280 net/socket.c:1223 sock_ioctl+0x228/0x6c0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (nr_node_list_lock){+...}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_rt_device_down+0xd5/0x7f0 net/netrom/nr_route.c:517 nr_device_event+0x126/0x170 net/netrom/af_netrom.c:126 notifier_call_chain+0xb7/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1996 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline] call_netdevice_notifiers net/core/dev.c:2048 [inline] __dev_notify_flags+0x1f9/0x2e0 net/core/dev.c:8992 dev_change_flags+0x10c/0x160 net/core/dev.c:9028 dev_ifsioc+0x9c8/0x10b0 net/core/dev_ioctl.c:526 dev_ioctl+0x224/0x10c0 net/core/dev_ioctl.c:783 sock_do_ioctl+0x19e/0x280 net/socket.c:1223 sock_ioctl+0x228/0x6c0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (nr_neigh_list_lock){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 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_del_node net/netrom/nr_route.c:342 [inline] nr_rt_ioctl+0x207f/0x29e0 net/netrom/nr_route.c:678 nr_ioctl+0x19a/0x2e0 net/netrom/af_netrom.c:1254 sock_do_ioctl+0x116/0x280 net/socket.c:1209 sock_ioctl+0x228/0x6c0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 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_neigh_list_lock --> nr_node_list_lock --> &nr_node->node_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&nr_node->node_lock); lock(nr_node_list_lock); lock(&nr_node->node_lock); lock(nr_neigh_list_lock); *** DEADLOCK *** 2 locks held by syz.3.32/6172: #0: ffffffff9012a558 (nr_node_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #0: ffffffff9012a558 (nr_node_list_lock){+...}-{3:3}, at: nr_del_node net/netrom/nr_route.c:334 [inline] #0: ffffffff9012a558 (nr_node_list_lock){+...}-{3:3}, at: nr_rt_ioctl+0x22e/0x29e0 net/netrom/nr_route.c:678 #1: ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] #1: ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: nr_del_node net/netrom/nr_route.c:335 [inline] #1: ffff88810370fa70 (&nr_node->node_lock){+...}-{3:3}, at: nr_rt_ioctl+0x2aa/0x29e0 net/netrom/nr_route.c:678 stack backtrace: CPU: 3 UID: 0 PID: 6172 Comm: syz.3.32 Not tainted 6.13.0-rc6-syzkaller-00038-g09a0fa92e5b4 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 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_del_node net/netrom/nr_route.c:342 [inline] nr_rt_ioctl+0x207f/0x29e0 net/netrom/nr_route.c:678 nr_ioctl+0x19a/0x2e0 net/netrom/af_netrom.c:1254 sock_do_ioctl+0x116/0x280 net/socket.c:1209 sock_ioctl+0x228/0x6c0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbff7985d29 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fbff8769038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fbff7b75fa0 RCX: 00007fbff7985d29 RDX: 0000000020000180 RSI: 000000000000890c RDI: 0000000000000005 RBP: 00007fbff7a01b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fbff7b75fa0 R15: 00007ffd23708838 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup