Warning: Permanently added '10.128.15.221' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 63.870419][ T6844] IPVS: ftp: loaded support on port[0] = 21 [ 63.927619][ T6844] IPVS: ftp: loaded support on port[0] = 21 [ 63.982274][ T328] tipc: TX() has been purged, node left! [ 64.004658][ T6844] [ 64.007007][ T6844] ====================================================== [ 64.014084][ T6844] WARNING: possible circular locking dependency detected [ 64.021202][ T6844] 5.9.0-rc2-next-20200828-syzkaller #0 Not tainted [ 64.027670][ T6844] ------------------------------------------------------ [ 64.034679][ T6844] syz-executor061/6844 is trying to acquire lock: [ 64.041059][ T6844] ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 [ 64.051479][ T6844] [ 64.051479][ T6844] but task is already holding lock: [ 64.058920][ T6844] ffff88808651a210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 [ 64.068976][ T6844] [ 64.068976][ T6844] which lock already depends on the new lock. [ 64.068976][ T6844] [ 64.079355][ T6844] [ 64.079355][ T6844] the existing dependency chain (in reverse order) is: [ 64.088353][ T6844] [ 64.088353][ T6844] -> #3 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}: [ 64.097040][ T6844] down_write+0x8d/0x150 [ 64.101776][ T6844] __sock_release+0x86/0x280 [ 64.106873][ T6844] sock_close+0x18/0x20 [ 64.111534][ T6844] __fput+0x285/0x920 [ 64.116008][ T6844] delayed_fput+0x56/0x70 [ 64.120843][ T6844] process_one_work+0x94c/0x1670 [ 64.126276][ T6844] worker_thread+0x64c/0x1120 [ 64.131445][ T6844] kthread+0x3b5/0x4a0 [ 64.136008][ T6844] ret_from_fork+0x1f/0x30 [ 64.140914][ T6844] [ 64.140914][ T6844] -> #2 ((delayed_fput_work).work){+.+.}-{0:0}: [ 64.149332][ T6844] process_one_work+0x8bb/0x1670 [ 64.154765][ T6844] worker_thread+0x64c/0x1120 [ 64.159934][ T6844] kthread+0x3b5/0x4a0 [ 64.164499][ T6844] ret_from_fork+0x1f/0x30 [ 64.169403][ T6844] [ 64.169403][ T6844] -> #1 ((wq_completion)events){+.+.}-{0:0}: [ 64.177536][ T6844] flush_workqueue+0x110/0x13e0 [ 64.182881][ T6844] tipc_exit_net+0x47/0x2a0 [ 64.187877][ T6844] ops_exit_list+0xb0/0x160 [ 64.192883][ T6844] cleanup_net+0x4ea/0xb10 [ 64.197794][ T6844] process_one_work+0x94c/0x1670 [ 64.203234][ T6844] worker_thread+0x64c/0x1120 [ 64.208405][ T6844] kthread+0x3b5/0x4a0 [ 64.212968][ T6844] ret_from_fork+0x1f/0x30 [ 64.217878][ T6844] [ 64.217878][ T6844] -> #0 (pernet_ops_rwsem){++++}-{3:3}: [ 64.225592][ T6844] __lock_acquire+0x2a6b/0x5640 [ 64.230947][ T6844] lock_acquire+0x1f1/0xad0 [ 64.235944][ T6844] down_write+0x8d/0x150 [ 64.240678][ T6844] unregister_netdevice_notifier+0x1e/0x170 [ 64.247065][ T6844] raw_release+0x58/0x890 [ 64.251888][ T6844] __sock_release+0xcd/0x280 [ 64.256969][ T6844] sock_close+0x18/0x20 [ 64.261616][ T6844] __fput+0x285/0x920 [ 64.266090][ T6844] task_work_run+0xdd/0x190 [ 64.271084][ T6844] do_exit+0xb7d/0x29f0 [ 64.275746][ T6844] do_group_exit+0x125/0x310 [ 64.280832][ T6844] __x64_sys_exit_group+0x3a/0x50 [ 64.286360][ T6844] do_syscall_64+0x2d/0x70 [ 64.291276][ T6844] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 64.297680][ T6844] [ 64.297680][ T6844] other info that might help us debug this: [ 64.297680][ T6844] [ 64.307881][ T6844] Chain exists of: [ 64.307881][ T6844] pernet_ops_rwsem --> (delayed_fput_work).work --> &sb->s_type->i_mutex_key#13 [ 64.307881][ T6844] [ 64.322787][ T6844] Possible unsafe locking scenario: [ 64.322787][ T6844] [ 64.330296][ T6844] CPU0 CPU1 [ 64.335647][ T6844] ---- ---- [ 64.340982][ T6844] lock(&sb->s_type->i_mutex_key#13); [ 64.346415][ T6844] lock((delayed_fput_work).work); [ 64.354115][ T6844] lock(&sb->s_type->i_mutex_key#13); [ 64.362065][ T6844] lock(pernet_ops_rwsem); [ 64.366554][ T6844] [ 64.366554][ T6844] *** DEADLOCK *** [ 64.366554][ T6844] [ 64.374672][ T6844] 1 lock held by syz-executor061/6844: [ 64.380110][ T6844] #0: ffff88808651a210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 [ 64.390602][ T6844] [ 64.390602][ T6844] stack backtrace: [ 64.396470][ T6844] CPU: 0 PID: 6844 Comm: syz-executor061 Not tainted 5.9.0-rc2-next-20200828-syzkaller #0 [ 64.406322][ T6844] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.416360][ T6844] Call Trace: [ 64.419638][ T6844] dump_stack+0x18f/0x20d [ 64.423955][ T6844] check_noncircular+0x324/0x3e0 [ 64.428865][ T6844] ? print_circular_bug+0x3a0/0x3a0 [ 64.434036][ T6844] ? find_held_lock+0x2d/0x110 [ 64.438774][ T6844] ? is_bpf_text_address+0xa9/0x160 [ 64.443948][ T6844] ? lock_repin_lock+0x460/0x460 [ 64.448855][ T6844] ? mark_lock+0xbc/0x1710 [ 64.453246][ T6844] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 64.459298][ T6844] __lock_acquire+0x2a6b/0x5640 [ 64.464127][ T6844] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 64.470079][ T6844] lock_acquire+0x1f1/0xad0 [ 64.474568][ T6844] ? unregister_netdevice_notifier+0x1e/0x170 [ 64.480614][ T6844] ? lock_release+0x8e0/0x8e0 [ 64.485266][ T6844] ? lock_is_held_type+0xbb/0xf0 [ 64.490175][ T6844] ? __sock_release+0x86/0x280 [ 64.494912][ T6844] down_write+0x8d/0x150 [ 64.499130][ T6844] ? unregister_netdevice_notifier+0x1e/0x170 [ 64.505178][ T6844] ? down_write_killable+0x170/0x170 [ 64.510444][ T6844] ? _raw_spin_unlock_irqrestore+0x62/0xe0 [ 64.516224][ T6844] ? lock_is_held_type+0xbb/0xf0 [ 64.521136][ T6844] unregister_netdevice_notifier+0x1e/0x170 [ 64.527006][ T6844] raw_release+0x58/0x890 [ 64.531308][ T6844] ? fcntl_setlk+0xf60/0xf60 [ 64.535874][ T6844] __sock_release+0xcd/0x280 [ 64.540450][ T6844] sock_close+0x18/0x20 [ 64.544581][ T6844] __fput+0x285/0x920 [ 64.548536][ T6844] ? __sock_release+0x280/0x280 [ 64.553364][ T6844] task_work_run+0xdd/0x190 [ 64.557852][ T6844] do_exit+0xb7d/0x29f0 [ 64.561981][ T6844] ? mm_update_next_owner+0x7a0/0x7a0 [ 64.567326][ T6844] ? lock_is_held_type+0xbb/0xf0 [ 64.572235][ T6844] do_group_exit+0x125/0x310 [ 64.576799][ T6844] __x64_sys_exit_group+0x3a/0x50 [ 64.581810][ T6844] do_syscall_64+0x2d/0x70 [ 64.586198][ T6844] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 64.592060][ T6844] RIP: 0033:0x4400f8 [ 64.595921][ T6844] Code: Bad RIP value. [ 64.599956][ T6844] RSP: 002b:00007ffe7a415bc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 64.608362][ T6844] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000004400f8 [ 64.616306][ T6844] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 64.624265][ T6844] RBP: 00000000004c63f0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 64.632209][ T6844] R10: 00000000bb1414ac R11: 0000000000000246 R12: 0000000000000001 [ 64.640153][ T6844] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000