INFO: task syz.2.7145:30848 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.7145      state:D stack:27480 pid:30848 tgid:30847 ppid:28564  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_timeout+0xc3/0x2c0
 wait_for_completion+0x2cc/0x5e0
 __flush_work+0xa17/0xc50
 p9_fd_close+0x245/0x430
 p9_client_create+0x68d/0xc90
 v9fs_session_init+0x46/0xe60
 v9fs_get_tree+0xbd/0xac0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x341/0xd30
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6fb0f9ce59
RSP: 002b:00007f6fb1de3028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6fb1215fa0 RCX: 00007f6fb0f9ce59
RDX: 0000200000000080 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007f6fb1032d6f R08: 00002000000000c0 R09: 0000000000000000
R10: 000000000000008c R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6fb1216038 R14: 00007f6fb1215fa0 R15: 00007ffc0b6680e8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/1:1/31:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc90000a67c40 (p9_poll_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
5 locks held by sshd/5599:
5 locks held by kworker/0:6/22548:
 #0: ffff8881052d7940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc90003b9fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff88810c0551d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30
 #3: ffff88810d2771d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
 #4: ffff888118ce21a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450
3 locks held by kworker/1:7/27594:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc9000778fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff88801e8db250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0
2 locks held by getty/30167:
 #0: ffff88817254d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc90009ac32e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
4 locks held by udevd/30322:
 #0: ffff88801cba6ab8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10
 #1: ffff888112dfd080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420
 #2: ffff8881209120f8 (kn->active#26){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff88810d2771d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x389/0x470
 ret_from_fork+0x514/0xb70
 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: 1464 Comm: syz.6.7831 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:its_return_thunk+0x0/0x10
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 eb 64 86 f5 cc
RSP: 0018:ffffc9000964f408 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000005a44979c RSI: 0000000086db7919 RDI: ffff8881bc1f8000
RBP: ffffffff8176f256 R08: ffffffff8176f256 R09: ffffffff8e95cce0
R10: ffffc9000964f5f8 R11: ffffffff81b0f070 R12: 0000000000000002
R13: ffffffff8e95cce0 R14: 0000000000000000 R15: 0000000000000246
FS:  00007f1baf7ed6c0(0000) GS:ffff88818dc84000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f438cc87e20 CR3: 000000000e74a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 unwind_next_frame+0xc3/0x2550
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 save_stack+0x122/0x230
 __reset_page_owner+0x71/0x1f0
 free_pages_prepare+0x972/0xa70
 __free_contig_range_common+0x174/0x340
 free_pages_bulk+0x48/0x120
 vfree+0x224/0x490
 kcov_close+0x28/0x50
 __fput+0x44f/0xa60
 task_work_run+0x1d9/0x270
 do_exit+0x70f/0x22c0
 do_group_exit+0x21b/0x2d0
 get_signal+0x1284/0x1330
 arch_do_signal_or_restart+0xbc/0x840
 exit_to_user_mode_loop+0x8c/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bae99ce59
Code: Unable to access opcode bytes at 0x7f1bae99ce2f.
RSP: 002b:00007f1baf7ed0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f1baec16098 RCX: 00007f1bae99ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1baec16098
RBP: 00007f1baec16090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1baec16128 R14: 00007ffe11b90d70 R15: 00007ffe11b90e58
 </TASK>
