Warning: Permanently added '10.128.0.56' (ECDSA) to the list of known hosts. executing program [ 63.356656][ T6857] IPVS: ftp: loaded support on port[0] = 21 [ 63.408420][ T6857] IPVS: ftp: loaded support on port[0] = 21 [ 63.563665][ T197] [ 63.566101][ T197] ====================================================== [ 63.573159][ T197] WARNING: possible circular locking dependency detected [ 63.580213][ T197] 5.9.0-rc2-next-20200828-syzkaller #0 Not tainted [ 63.586702][ T197] ------------------------------------------------------ [ 63.593734][ T197] kworker/u4:5/197 is trying to acquire lock: [ 63.599783][ T197] ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x13e0 [ 63.609526][ T197] [ 63.609526][ T197] but task is already holding lock: [ 63.616904][ T197] ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 [ 63.625769][ T197] [ 63.625769][ T197] which lock already depends on the new lock. [ 63.625769][ T197] [ 63.636159][ T197] [ 63.636159][ T197] the existing dependency chain (in reverse order) is: [ 63.645159][ T197] [ 63.645159][ T197] -> #3 (pernet_ops_rwsem){++++}-{3:3}: [ 63.652884][ T197] down_write+0x8d/0x150 [ 63.657642][ T197] unregister_netdevice_notifier+0x1e/0x170 [ 63.664051][ T197] bcm_release+0x94/0x750 [ 63.668908][ T197] __sock_release+0xcd/0x280 [ 63.674018][ T197] sock_close+0x18/0x20 [ 63.679057][ T197] __fput+0x285/0x920 [ 63.683562][ T197] task_work_run+0xdd/0x190 [ 63.688610][ T197] exit_to_user_mode_prepare+0x195/0x1c0 [ 63.694784][ T197] syscall_exit_to_user_mode+0x59/0x2b0 [ 63.700871][ T197] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 63.707267][ T197] [ 63.707267][ T197] -> #2 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}: [ 63.715963][ T197] down_write+0x8d/0x150 [ 63.720714][ T197] __sock_release+0x86/0x280 [ 63.725814][ T197] sock_close+0x18/0x20 [ 63.730518][ T197] __fput+0x285/0x920 [ 63.735099][ T197] delayed_fput+0x56/0x70 [ 63.739939][ T197] process_one_work+0x94c/0x1670 [ 63.745391][ T197] worker_thread+0x64c/0x1120 [ 63.750577][ T197] kthread+0x3b5/0x4a0 [ 63.755156][ T197] ret_from_fork+0x1f/0x30 [ 63.760069][ T197] [ 63.760069][ T197] -> #1 ((delayed_fput_work).work){+.+.}-{0:0}: [ 63.768494][ T197] process_one_work+0x8bb/0x1670 [ 63.773961][ T197] worker_thread+0x64c/0x1120 [ 63.779148][ T197] kthread+0x3b5/0x4a0 [ 63.783736][ T197] ret_from_fork+0x1f/0x30 [ 63.788660][ T197] [ 63.788660][ T197] -> #0 ((wq_completion)events){+.+.}-{0:0}: [ 63.796906][ T197] __lock_acquire+0x2a6b/0x5640 [ 63.802268][ T197] lock_acquire+0x1f1/0xad0 [ 63.807296][ T197] flush_workqueue+0x110/0x13e0 [ 63.812680][ T197] tipc_exit_net+0x47/0x2a0 [ 63.817708][ T197] ops_exit_list+0xb0/0x160 [ 63.822804][ T197] cleanup_net+0x4ea/0xb10 [ 63.827731][ T197] process_one_work+0x94c/0x1670 [ 63.833201][ T197] worker_thread+0x64c/0x1120 [ 63.838394][ T197] kthread+0x3b5/0x4a0 [ 63.842971][ T197] ret_from_fork+0x1f/0x30 [ 63.847883][ T197] [ 63.847883][ T197] other info that might help us debug this: [ 63.847883][ T197] [ 63.858108][ T197] Chain exists of: [ 63.858108][ T197] (wq_completion)events --> &sb->s_type->i_mutex_key#13 --> pernet_ops_rwsem [ 63.858108][ T197] [ 63.872772][ T197] Possible unsafe locking scenario: [ 63.872772][ T197] [ 63.880222][ T197] CPU0 CPU1 [ 63.885585][ T197] ---- ---- [ 63.890946][ T197] lock(pernet_ops_rwsem); [ 63.895449][ T197] lock(&sb->s_type->i_mutex_key#13); [ 63.903414][ T197] lock(pernet_ops_rwsem); [ 63.910422][ T197] lock((wq_completion)events); [ 63.915357][ T197] [ 63.915357][ T197] *** DEADLOCK *** [ 63.915357][ T197] [ 63.923494][ T197] 3 locks held by kworker/u4:5/197: [ 63.928692][ T197] #0: ffff8880a97b1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 [ 63.938955][ T197] #1: ffffc90001107da8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 [ 63.948871][ T197] #2: ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 [ 63.958173][ T197] [ 63.958173][ T197] stack backtrace: [ 63.964060][ T197] CPU: 0 PID: 197 Comm: kworker/u4:5 Not tainted 5.9.0-rc2-next-20200828-syzkaller #0 [ 63.973604][ T197] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.984066][ T197] Workqueue: netns cleanup_net [ 63.988823][ T197] Call Trace: [ 63.992224][ T197] dump_stack+0x18f/0x20d [ 63.996564][ T197] check_noncircular+0x324/0x3e0 [ 64.001519][ T197] ? print_circular_bug+0x3a0/0x3a0 [ 64.006728][ T197] ? find_held_lock+0x2d/0x110 [ 64.011484][ T197] ? free_obj_work+0x590/0x590 [ 64.016256][ T197] ? lock_repin_lock+0x460/0x460 [ 64.021189][ T197] ? mark_lock+0xbc/0x1710 [ 64.025617][ T197] __lock_acquire+0x2a6b/0x5640 [ 64.030469][ T197] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 64.036443][ T197] ? mark_lock+0xbc/0x1710 [ 64.040856][ T197] ? add_wait_queue_exclusive+0x180/0x180 [ 64.046579][ T197] lock_acquire+0x1f1/0xad0 [ 64.051345][ T197] ? flush_workqueue+0xe1/0x13e0 [ 64.056292][ T197] ? lock_release+0x8e0/0x8e0 [ 64.060973][ T197] ? lockdep_init_map_waits+0x26a/0x8a0 [ 64.066965][ T197] ? lockdep_init_map_waits+0x26a/0x8a0 [ 64.072538][ T197] ? __raw_spin_lock_init+0x34/0x100 [ 64.077825][ T197] flush_workqueue+0x110/0x13e0 [ 64.082684][ T197] ? flush_workqueue+0xe1/0x13e0 [ 64.087641][ T197] ? lock_acquire+0x1f1/0xad0 [ 64.092329][ T197] ? tipc_net_stop+0x3c/0x310 [ 64.096999][ T197] ? find_held_lock+0x2d/0x110 [ 64.101757][ T197] ? max_active_store+0x120/0x120 [ 64.106777][ T197] ? tipc_init_net+0x5c0/0x5c0 [ 64.111641][ T197] tipc_exit_net+0x47/0x2a0 [ 64.116160][ T197] ? tipc_init_net+0x5c0/0x5c0 [ 64.120928][ T197] ops_exit_list+0xb0/0x160 [ 64.125423][ T197] cleanup_net+0x4ea/0xb10 [ 64.129834][ T197] ? ops_free_list.part.0+0x3d0/0x3d0 [ 64.135198][ T197] ? lock_is_held_type+0xbb/0xf0 [ 64.140143][ T197] process_one_work+0x94c/0x1670 [ 64.145075][ T197] ? lock_release+0x8e0/0x8e0 [ 64.149760][ T197] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 64.155145][ T197] ? rwlock_bug.part.0+0x90/0x90 [ 64.160095][ T197] worker_thread+0x64c/0x1120 [ 64.164765][ T197