INFO: task syz.2.25:6011 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.25        state:D stack:24856 pid:6011  tgid:6010  ppid:5822   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x153c/0x4fe0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8d6dd9acb9
RSP: 002b:00007f8d6ec98028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f8d6e015fa0 RCX: 00007f8d6dd9acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f8d6e015fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8d6e016038 R14: 00007f8d6e015fa0 R15: 00007fff80031548
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e33f020 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/1:2/782:
 #0: ffff88810006d948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0
 #1: ffffc90005b97c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0
 #2: ffff888169f33240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0
1 lock held by dhcpcd/5556:
 #0: ffffffff8f717a48 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_deladdr+0x23d/0x370
2 locks held by getty/5636:
 #0: ffff8881072a90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000357b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by sshd/5733:
1 lock held by syz-executor/5814:
5 locks held by kworker/u8:2/5826:
 #0: ffff888100eef948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0
 #1: ffffc900051b7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0
 #2: ffffffff8f70a430 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0
 #3: ffffffff8f717a48 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0xa10
 #4: ffffffff8e344638 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
1 lock held by syz.2.25/6011:
 #0: ffff8881077040e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.39/6124:
 #0: ffff8881077040e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.3.39/6127:
 #0: ffff8881077040e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.0.324/7944:
 #0: ffff8881077040e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x289/0x3d0
1 lock held by syz.3.421/8512:
 #0: ffff8881077040e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
7 locks held by syz-executor/8616:
 #0: ffff8881155de420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90
 #1: ffff888174f87c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540
 #2: ffff88810b37b788 (kn->active#48){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540
 #3: ffffffff8efa2e68 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370
 #4: ffff8881745520e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x800
 #5: ffff888174550250 (&devlink->lock_key#7){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160
 #6: ffffffff8e344500 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580
1 lock held by syz.4.450/8681:
 #0: ffffffff8e344638 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770

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

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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xe83/0xed0
 kthread+0x388/0x470
 ret_from_fork+0x51b/0xa40
 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: 8681 Comm: syz.4.450 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:stack_depot_save_flags+0x7b/0x810
Code: 12 42 8d 2c d5 7b 71 f5 75 83 fe 04 72 6f 89 e8 89 e9 4c 89 f2 03 0a 03 42 04 03 6a 08 89 ef c1 c7 04 29 e9 31 cf 01 c5 29 f8 <41> 89 f8 41 c1 c0 06 41 31 c0 01 ef 45 89 c1 41 c1 c1 08 44 29 c5
RSP: 0018:ffffc90005eb7708 EFLAGS: 00000202
RAX: 000000005004f0e0 RBX: ffff88810aa14e00 RCX: 000000006e8f4900
RDX: ffffc90005eb77dc RSI: 0000000000000009 RDI: 000000002ee73aec
RBP: 0000000042f2b30a R08: 000000004cb0083d R09: 000000006af85223
R10: 000000000000000c R11: ffffffff81adf2a0 R12: dffffc0000000000
R13: 0000000000002000 R14: ffffc90005eb77a0 R15: 1ffff92000bd6ef0
FS:  0000000000000000(0000) GS:ffff88818e3f4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c1e4b02698 CR3: 000000017548c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 save_stack+0x130/0x230
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xb81/0xce0
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44f/0xa70
 task_work_run+0x1d9/0x270
 do_exit+0x69b/0x2310
 do_group_exit+0x21b/0x2d0
 get_signal+0x1284/0x1330
 arch_do_signal_or_restart+0xbc/0x830
 exit_to_user_mode_loop+0x86/0x480
 do_syscall_64+0x2b7/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa4fe99acb9
Code: Unable to access opcode bytes at 0x7fa4fe99ac8f.
RSP: 002b:00007ffecd217408 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 000000000003597b RCX: 00007fa4fe99acb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa4fec15fac
RBP: 0000000000000fd2 R08: 3fffffffffffffff R09: 0000000000000000
R10: 00007ffecd217510 R11: 0000000000000246 R12: 00007ffecd217530
R13: 00007fa4fec15fac R14: 000000000003694d R15: 00007ffecd217510
 </TASK>
