INFO: task syz.1.8204:24380 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.8204      state:D stack:26944 pid:24380 tgid:24379 ppid:5978   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 nfsd_nl_listener_set_doit+0x141/0x1670
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0x972/0x9f0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9ae879cdd9
RSP: 002b:00007f9ae9592028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9ae8a15fa0 RCX: 00007f9ae879cdd9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000006
RBP: 00007f9ae8832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9ae8a16038 R14: 00007f9ae8a15fa0 R15: 00007ffc3b6af228
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5637:
 #0: ffff888175d4e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by sshd/5733:
1 lock held by syz-executor/5974:
2 locks held by syz.2.5571/18442:
 #0: ffffffff8fc3e930 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ea86b88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670
2 locks held by syz.1.8204/24380:
 #0: ffffffff8fc3e930 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ea86b88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670
1 lock held by syz-executor/24903:
 #0: ffffffff8e7648f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
2 locks held by syz.3.10266/29080:
 #0: ffffffff8fc3e930 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ea86b88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x17c/0xc40
1 lock held by syz.0.12036/606:
 #0: ffffffff8e7648f8 (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+0xfd9/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 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: 24903 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+0x35e/0x2cf0
Code: 09 d4 41 09 cc 41 09 dc 45 89 64 c7 20 41 89 7c c7 24 4c 89 7c 24 20 4d 8d 2c c7 41 81 e4 ff 1f 00 00 4c 0f a3 25 02 e7 82 12 <73> 15 49 69 c4 c8 00 00 00 48 8d 80 10 94 c5 93 4c 8b 74 24 08 eb
RSP: 0018:ffffc90004857940 EFLAGS: 00000007
RAX: 0000000000000000 RBX: 0000000000048000 RCX: 0000000000000027
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff82214f9f R09: ffff888121040f18
R10: dffffc0000000000 R11: fffff5200090af50 R12: 0000000000000027
R13: ffff8881960545d8 R14: ffff888196053a80 R15: ffff8881960545d8
FS:  0000555570b1b500(0000) GS:ffff88818de54000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e714ff8 CR3: 0000000113cca000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0xf0/0x2e0
 _raw_spin_trylock+0x47/0x80
 __free_frozen_pages+0x6cf/0xdb0
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44f/0xa70
 task_work_run+0x1d9/0x270
 do_exit+0x70f/0x23c0
 do_group_exit+0x21b/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x221a/0x2240
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd3a359cdd9
Code: Unable to access opcode bytes at 0x7fd3a359cdaf.
RSP: 002b:00007ffe15a8f628 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fd3a3633cb1 RCX: 00007fd3a359cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007fd3a3633cc3 R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 000000000008aa2d R15: 00007ffe15a8f7d0
 </TASK>
