INFO: task syz.2.7641:23933 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.7641      state:D stack:27200 pid:23933 tgid:23931 ppid:5612   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x17d4/0x5820 kernel/sched/core.c:7270
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7362
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 nfsd_nl_listener_get_doit+0x104/0x610 fs/nfsd/nfsctl.c:2197
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0x54e/0x850 net/socket.c:2713
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
 __sys_sendmsg net/socket.c:2799 [inline]
 __do_sys_sendmsg net/socket.c:2804 [inline]
 __se_sys_sendmsg net/socket.c:2802 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f752039e159
RSP: 002b:00007f752129a028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f7520625fa0 RCX: 00007f752039e159
RDX: 0000000004004990 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007f7520435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7520626038 R14: 00007f7520625fa0 R15: 00007ffeaacf9e18
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#1:
 #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
 #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline]
 #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
 #1: ffffffff9ad2aff8 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline]
 #1: ffffffff9ad2aff8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413
locks held by khungtaskd/32: 1, last CPU#0:
 #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6837
locks held by udevd/4978: 1, last CPU#0:
 #0: ffff88801c2cc980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0x9e/0x650 fs/kernfs/dir.c:1217
locks held by getty/5363: 2, on CPU#0:
 #0: ffff8880359460a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/5622: 4, last CPU#0:
 #0: ffffffff8ee35b90 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8ee35b90 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1595
 #1: ffff8880346adcf8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff8880346adcf8 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff888078cc1078 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff888078cc1078 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by udevd/5905: 2, last CPU#0:
 #0: ffff888036388460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
 #1: ffff8880b8624408 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
locks held by udevd/6285: 4, last CPU#0:
 #0: ffff888036388460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
 #1: ffff8880317cf520 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff8880317cf520 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_open+0x242/0x1a40 fs/namei.c:4458
 #2: ffffffff8f4eeab8 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
 #2: ffffffff8f4eeab8 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:305 [inline]
 #2: ffffffff8f4eeab8 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock security/tomoyo/common.h:1112 [inline]
 #2: ffffffff8f4eeab8 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_path_number_perm+0x219/0x5f0 security/tomoyo/file.c:727
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.5.5340/18611: 2, on CPU#1:
 #0: ffffffff902c0be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8f09e380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz-executor/19058: 4, last CPU#1:
 #0: ffffffff8ee35b90 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8ee35b90 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1595
 #1: ffff88802a43b6b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff88802a43b6b8 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff888078cc5cf8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff888078cc5cf8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.2.7641/23933: 2, on CPU#1:
 #0: ffffffff902c0be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8f09e380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x104/0x610 fs/nfsd/nfsctl.c:2197
locks held by syz-executor/26755: 4, last CPU#0:
 #0: ffffffff8ee35b90 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8ee35b90 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1595
 #1: ffff888076cf5038 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff888076cf5038 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff888078cc5038 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff888078cc5038 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.6.9153/27436: 2, last CPU#0:
 #0: ffff888035891d38 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
 #0: ffff888035891d38 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
 #1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 #1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.4.9175/27448: 3, last CPU#0:
 #0: ffff88801c2f2460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
 #0: ffff88801c2f2460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #1: ffff888034f5ef18 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff888034f5ef18 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3430
 #2: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 #2: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.8.9180/27453: 2, last CPU#1:
 #0: ffff8880349cf950 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline]
 #0: ffff8880349cf950 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: lookup_open+0x231/0x1a40 fs/namei.c:4460
 #1: ffff8880349cf690 (&ei->xattr_sem){++++}-{4:4}, at: ext4_find_inline_entry+0x134/0x650 fs/ext4/inline.c:1630

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
RIP: 0010:rdtsc_ordered arch/x86/include/asm/tsc.h:57 [inline]
RIP: 0010:delay_tsc+0x73/0xd0 arch/x86/lib/delay.c:70
Code: e8 32 43 b3 f5 65 48 8b 05 fa 68 b2 07 48 85 c0 74 1c f3 90 bf 01 00 00 00 e8 c9 41 b3 f5 e8 84 7a 01 00 39 c5 75 0e 0f 01 f9 <66> 90 eb bb e8 24 ce 51 f5 eb dd 4c 29 fb e8 6a 7a 01 00 89 c5 0f
RSP: 0018:ffffc900001578b8 EFLAGS: 00000046
RAX: 000000002df41676 RBX: 0000000000000993 RCX: 0000000000000001
RDX: 000000000000023c RSI: ffffffff8c6d8b60 RDI: ffffffff8c6d8b20
RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8be196c0 R12: 1ffffffff35a5659
R13: 00000000ffffffff R14: 0000023c2df40e85 R15: 000000000000075e
FS:  0000000000000000(0000) GS:ffff888124de0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe5289eb840 CR3: 000000005ab91000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 udelay include/asm-generic/delay.h:62 [inline]
 wait_for_lsr+0x147/0x2f0 drivers/tty/serial/8250/8250_port.c:2019
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3270 [inline]
 __serial8250_console_fifo_write+0xcd/0x3e0 drivers/tty/serial/8250/8250_port.c:3345
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
 __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
 serial8250_console_write+0xaa1/0x1200 drivers/tty/serial/8250/8250_port.c:3493
 nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
 nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>