INFO: task syz.6.173:7547 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.173       state:D stack:22776 pid:7547  tgid:7546  ppid:7099   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 drop_caches_sysctl_handler+0x97/0x170
 proc_sys_call_handler+0x4c6/0x700
 iter_file_splice_write+0x975/0x10e0
 direct_splice_actor+0x101/0x160
 splice_direct_to_actor+0x5a8/0xcc0
 do_splice_direct+0x181/0x270
 do_sendfile+0x4da/0x7e0
 __se_sys_sendfile64+0xd9/0x190
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe327b8ebe9
RSP: 002b:00007fe325df6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fe327db5fa0 RCX: 00007fe327b8ebe9
RDX: 00002000000000c0 RSI: 0000000000000006 RDI: 0000000000000007
RBP: 00007fe327c11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe327db6038 R14: 00007fe327db5fa0 R15: 00007ffc6b0d7918
 </TASK>
INFO: task syz.3.196:7831 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.196       state:D stack:26536 pid:7831  tgid:7826  ppid:6203   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f60c638ebe9
RSP: 002b:00007f60c720c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f60c65b6090 RCX: 00007f60c638ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f60c65b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f60c65b6128 R14: 00007f60c65b6090 R15: 00007ffffc0eabd8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5671:
 #0: ffff8880211710a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc90001dfa2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by syz-executor/5852:
3 locks held by kworker/1:3/5893:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000472fbc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e13f978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
2 locks held by syz.6.173/7547:
 #0: ffff888026224428 (sb_writers#3){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x160
 #1: ffff8880346620e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.196/7831:
 #0: ffff8880346620e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.4.456/9472:
 #0: ffff8880346620e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/10135:
2 locks held by dhcpcd/10177:

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

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: 10135 Comm: syz-executor 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:__lock_acquire+0x862/0xd20
Code: 31 c8 01 d6 29 c2 89 c1 c1 c1 10 31 d1 01 f0 41 89 cf 41 c1 c7 13 29 ce 41 31 f7 01 c1 44 29 f8 44 01 f9 41 c1 c7 04 41 31 c7 <49> c1 e7 20 49 09 cf 83 3d 84 54 06 0e 00 0f 85 36 02 00 00 48 83
RSP: 0018:ffffc900043ef650 EFLAGS: 00000002
RAX: 0000000048aa0974 RBX: 0000000000000000 RCX: 0000000076153240
RDX: 000000000000413d RSI: 00000000414040f8 RDI: ffff88801eead640
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff84d0510a
R10: dffffc0000000000 R11: fffffbfff1f47147 R12: 0000000000000001
R13: ffff88801eeae130 R14: ffff88801eeae130 R15: 000000003df1592f
FS:  0000555566447500(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d4b654b000 CR3: 0000000027c86000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360
 _raw_spin_lock_irqsave+0xa7/0xf0
 debug_check_no_obj_freed+0x17a/0x470
 remove_vm_area+0x1d3/0x300
 vfree+0x63/0x400
 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: 0033:0x7f68e8190a7c
Code: Unable to access opcode bytes at 0x7f68e8190a52.
RSP: 002b:00007ffdc716d440 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: 0000000000000030 RBX: 00007f68e8ee35c0 RCX: 00007f68e8190a7c
RDX: 0000000000000030 RSI: 00007f68e8ee3610 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00007ffdc716d494 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000006
R13: 0000000000000000 R14: 00007f68e8ee3610 R15: 0000000000000000
 </TASK>
