INFO: task syz.2.3580:21451 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.3580      state:D stack:26152 pid:21451 tgid:21450 ppid:5598   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 nfsd_nl_threads_get_doit+0x1c0/0x790
 genl_family_rcv_msg_doit+0x233/0x340
 genl_rcv_msg+0x614/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 ____sys_sendmsg+0x54e/0x850
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1b1/0x290
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f146979e559
RSP: 002b:00007f146a63b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1469a25fa0 RCX: 00007f146979e559
RDX: 000000000000c000 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007f14698358b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1469a26038 R14: 00007f1469a25fa0 R15: 00007ffd7a5c1108
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/36: 1, last CPU#1:
 #0: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5426: 2, on CPU#0:
 #0: ffff888102ab60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034932e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by kworker/u8:9/6981: 3, last CPU#1:
 #0: ffff88810d529140 ((wq_completion)krds_cp_wq#4/7){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc900067dfc40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffff888110bca480 (&tc->t_conn_path_lock){+.+.}-{4:4}, at: rds_tcp_conn_path_connect+0x1cc/0x920
locks held by syz.1.2754/18068: 2, on CPU#1:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0
locks held by syz.2.3580/21451: 2, on CPU#0:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790
locks held by syz.4.3992/23264: 2, on CPU#0:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0
locks held by kworker/u9:15/24094: 2, on CPU#0:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc90008137c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
locks held by syz.5.4199/24271: 2, on CPU#1:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790
locks held by syz.3.4303/24723: 2, on CPU#1:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_unlock_filesystem_doit+0x2af/0x410
locks held by syz.0.4611/26045: 2, on CPU#1:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0
locks held by syz.0.4611/26047: 2, on CPU#1:
 #0: ffffffff912c6388 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff9009f5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0
locks held by syz.7.4869/27171: 3, on CPU#0:
 #0: ffffffff909c9ea8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff91255800 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30
 #2: ffffffff8fd62c68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
locks held by syz.6.4870/27192: 2, last CPU#1:
 #0: ffff888111081bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0
 #1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240
locks held by modprobe/27194: 1, last CPU#0:
 #0: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 36 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+0x17d/0x390
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x38b/0x480
 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: 27194 Comm: modprobe 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:link_path_walk+0x796/0x1910
Code: 24 38 31 ff 44 89 fe e8 d8 a9 76 ff 45 85 ff 0f 84 b3 0d 00 00 4c 89 f0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 f7 e8 1a 76 e7 ff <49> 8b 06 41 ff cf 49 63 cf 48 8d 0c 49 48 c1 e1 04 4c 8d 34 08 49
RSP: 0018:ffffc90006e078a0 EFLAGS: 00000246
RAX: 1ffff92000dc0f60 RBX: ffffc90006e07ad8 RCX: ffff88811dfbbc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffff88811dfbbc00 R09: 0000000000000002
R10: 0000000000002e2e R11: 0000000000000000 R12: ffffc90006e07ad0
R13: ffffc90006e07af0 R14: ffffc90006e07b00 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88818c4c3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd72341ff0 CR3: 000000002c344000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 path_lookupat+0xe4/0x8c0
 filename_lookup+0x265/0x5d0
 vfs_statx+0xfc/0x200
 vfs_fstatat+0x11b/0x170
 __x64_sys_newfstatat+0x151/0x200
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb12fa528a9
Code: 49 01 00 09 00 00 00 83 c8 ff c3 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 00 00 00 00 41 89 ca b8 06 01 00 00 0f 05 <45> 31 c0 3d 00 f0 ff ff 76 0c f7 d8 41 83 c8 ff 89 05 a1 49 01 00
RSP: 002b:00007ffd72341938 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007fb12fa67ec0 RCX: 00007fb12fa528a9
RDX: 00007ffd723419e0 RSI: 00007ffd72341940 RDI: 00000000ffffff9c
RBP: 00007ffd72341aa0 R08: 0000000000080000 R09: 00007ffd72341940
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd72341940
R13: 0000000000000003 R14: 00007fb12fa64a40 R15: 00000000ffffffff
 </TASK>
