INFO: task syz-executor:9683 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:21928 pid:9683  tgid:9683  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: 0033:0x7ff97538ff17
RSP: 002b:00007ffd89407478 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007ff975411c05 RCX: 00007ff97538ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd89407530
RBP: 00007ffd89407530 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd894085c0
R13: 00007ff975411c05 R14: 0000000000029de5 R15: 00007ffd89408600
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 14613 Comm: syz.1.3036 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+0x67/0x2390
Code: 53 b0 00 48 89 5c 24 18 49 8b 5e 48 4d 8d 6e 38 4c 89 e8 48 c1 e8 03 48 89 44 24 58 80 3c 28 00 74 08 4c 89 ef e8 29 53 b0 00 <4d> 8b 7e 38 4d 89 f4 49 c1 ec 03 41 0f b6 04 2c 84 c0 0f 85 de 1b
RSP: 0018:ffffc9000454f538 EFLAGS: 00000246
RAX: 1ffff920008a9ec8 RBX: ffffffff81876d96 RCX: 146d5bd1137ddf00
RDX: dffffc0000000000 RSI: ffffffff81876d96 RDI: ffffc9000454f608
RBP: dffffc0000000000 R08: ffffc9000454f6d0 R09: 0000000000000007
R10: ffffc9000454f658 R11: ffffffff81ac3810 R12: ffff88801c733980
R13: ffffc9000454f640 R14: ffffc9000454f608 R15: ffffc9000454f608
FS:  000055557dbeb500(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4cee6fa8e5 CR3: 00000000215f6000 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: 0033:0x7f949c9c14a5
Code: Unable to access opcode bytes at 0x7f949c9c147b.
RSP: 002b:00007ffe04ba6100 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 0000000000000005 RCX: 00007f949c9c14a5
RDX: 00007ffe04ba6140 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000504ba645f
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f949cbb609c
R13: 00007f949cbb6090 R14: ffffffffffffffff R15: 00007ffe04ba6280
 </TASK>
