INFO: task syz-executor:5849 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:20504 pid:5849  tgid:5849  ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 v9fs_evict_inode+0x170/0x320
 evict+0x504/0x9c0
 __dentry_kill+0x209/0x660
 dput+0x19f/0x2b0
 shrink_dcache_for_umount+0xa0/0x170
 generic_shutdown_super+0x67/0x2c0
 kill_anon_super+0x3b/0x70
 v9fs_kill_super+0x4c/0x90
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ebf38ff17
RSP: 002b:00007ffd1a634078 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f0ebf411c05 RCX: 00007f0ebf38ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd1a634130
RBP: 00007ffd1a634130 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd1a6351c0
R13: 00007f0ebf411c05 R14: 0000000000011cbc R15: 00007ffd1a635200
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_exp_gp_kthr/18:
3 locks held by kworker/1:0/24:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900001c7bc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f537c88 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
4 locks held by kworker/u9:0/26:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900001efbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f537c88 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
 #3: ffffffff8e13f938 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/0:2/794:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000481fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88802bb46240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
1 lock held by syslogd/5280:
 #0: ffff88804b039f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
2 locks held by getty/5679:
 #0: ffff88801f51d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by kworker/u8:2/5717:
 #0: ffff88810834b948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002e9fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f537c88 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0
1 lock held by syz-executor/5849:
 #0: ffff88803317e0e0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.3.1477/9629:
 #0: ffff88803317e0e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.1497/9685:
 #0: ffff88803317e0e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/9807:
 #0: ffffffff8f537c88 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20
1 lock held by syz.4.1550/9849:
 #0: ffffffff8e13f938 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9849 Comm: syz.4.1550 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:unwind_next_frame+0x34e/0x2390
Code: 8f 0f 83 48 11 00 00 48 c7 c0 9c 76 b1 8f 49 29 c5 48 c7 c6 e4 7b 2a 90 49 c1 fd 02 4a 8d 14 6d 00 00 00 00 4c 01 ea 48 01 d2 <48> 01 f2 48 bd 00 00 00 00 00 fc ff df 0f 84 37 01 00 00 4c 8d 62
RSP: 0018:ffffc90008b2f538 EFLAGS: 00000246
RAX: ffffffff8fbf4a98 RBX: ffffffff8fbf4a9c RCX: ffffffff8fbf4aa0
RDX: 0000000000000000 RSI: ffffffff903f39e4 RDI: ffffffff8be332a0
RBP: ffffffff8fbf4aa0 R08: 0000000000000001 R09: ffffffff8172c195
R10: ffffc90008b2f658 R11: ffffffff81ac3910 R12: ffffffff82128da9
R13: 0000000000000000 R14: ffffc90008b2f608 R15: ffffffff8fbf4a9c
FS:  0000555593b92500(0000) GS:ffff8880b861c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6f51887e20 CR3: 0000000020cd2000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 save_stack+0xf5/0x1f0
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc4/0xd30
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5c5ad8ebe9
Code: Unable to access opcode bytes at 0x7f5c5ad8ebbf.
RSP: 002b:00007ffc9ba06348 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 00000000000361ad RCX: 00007f5c5ad8ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5c5afb5fac
RBP: 0000000000000032 R08: 7fffffffffffffff R09: 000000019ba0663f
R10: 00007ffc9ba06440 R11: 0000000000000246 R12: 00007f5c5afb5fac
R13: 00007ffc9ba06440 R14: 00000000000361df R15: 00007ffc9ba06460
 </TASK>
