INFO: task syz.6.924:10412 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.924       state:D stack:27016 pid:10412 ppid:8793   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 write_versions+0x96/0xe00 fs/nfsd/nfsctl.c:676
 nfsctl_transaction_write+0x10c/0x150 fs/nfsd/nfsctl.c:113
 vfs_write+0x299/0x9a0 fs/read_write.c:582
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc7bcb9e0d9
RSP: 002b:00007fc7bd985028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc7bce25fa0 RCX: 00007fc7bcb9e0d9
RDX: 0000000000000005 RSI: 0000200000000b00 RDI: 0000000000000003
RBP: 00007fc7bcc35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7bce26038 R14: 00007fc7bce25fa0 R15: 00007ffe752b7898
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by getty/5527:
 #0: ffff88814ce1d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
3 locks held by syz.0.637/8732:
 #0: ffff8880794f80c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040
 #1: ffff88805be22418 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #2: ffffffff8d3e1748 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb7/0xfa0 fs/nfsd/nfsctl.c:843
3 locks held by syz.6.924/10412:
 #0: ffff88801db379c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040
 #1: ffff888053504418 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
 #2: ffffffff8d3e1748 (nfsd_mutex){+.+.}-{3:3}, at: write_versions+0x96/0xe00 fs/nfsd/nfsctl.c:676
1 lock held by syz-executor/10747:
 #0: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #0: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf59/0xfa0 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12280 Comm: dhcpcd-run-hook Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x36/0x80 kernel/kcov.c:320
Code: d0 41 7c 7e 65 8b 15 d1 41 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 24 16 00 00 00 74 4e 8b 91 00 16 00 00 <83> fa 03 75 43 48 8b 91 08 16 00 00 44 8b 89 04 16 00 00 49 c1 e1
RSP: 0018:ffffc90004c8fd60 EFLAGS: 00000246
RAX: ffffffff81f6ef57 RBX: ffff888031015e78 RCX: ffff888021fdbc00
RDX: 0000000000000000 RSI: 000000000000000f RDI: ffffffffffffffff
RBP: 0000000000000000 R08: ffff888031015f17 R09: 1ffff11006202be2
R10: dffffc0000000000 R11: ffffed1006202be3 R12: 0000000000000003
R13: 0000000000000003 R14: ffff888031015e60 R15: 000000000000000f
FS:  00007f038075fc80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffece29da28 CR3: 000000004f532000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __set_open_fd fs/file.c:271 [inline]
 alloc_fd+0x407/0x640 fs/file.c:526
 do_sys_openat2+0x110/0x1d0 fs/open.c:1420
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f038091dc3a
Code: 41 89 f2 48 89 54 24 e0 41 83 e2 40 75 2a 89 f0 f7 d0 a9 00 00 41 00 74 1f 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 2e c3 0f 1f 44 00 00 48 8d 44 24 08 c7 44 24
RSP: 002b:00007ffece29f0f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f038091dc3a
RDX: 0000000000090800 RSI: 0000563fd9ab2520 RDI: 00000000ffffff9c
RBP: 0000563fd9ab228f R08: 00007f03809f9ac0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffece29f258
R13: 0000563fd9ab2288 R14: 0000000000000001 R15: 0000563fd9ab2547
 </TASK>