INFO: task syz.1.2951:11723 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2951      state:D stack:27184 pid:11723 ppid:  4192 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 write_versions+0x90/0xbb0 fs/nfsd/nfsctl.c:683
 nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
 vfs_write+0x304/0xd70 fs/read_write.c:592
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f34238bc019
RSP: 002b:00007f3421b14028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3423b43fa0 RCX: 00007f34238bc019
RDX: 0000000000000009 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f342395300c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3423b44038 R14: 00007f3423b43fa0 R15: 00007fff8835d688
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/u4:1/144:
 #0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
 #1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x517/0x810 kernel/sched/psi.c:891
1 lock held by klogd/3548:
 #0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
2 locks held by getty/3941:
 #0: ffff88802bf26098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by syz.2.2831/11428:
 #0: ffff8880212985f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88805c364460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8c571728 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:848
3 locks held by syz.1.2951/11723:
 #0: ffff888028f54370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff888024ba0460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8c571728 (nfsd_mutex){+.+.}-{3:3}, at: write_versions+0x90/0xbb0 fs/nfsd/nfsctl.c:683
3 locks held by syz.3.3078/12016:
 #0: ffff88805f277c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88802ac3a460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8c571728 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:848
3 locks held by syz.6.3178/12292:
 #0: ffff888076f98d70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88805d0d6460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8c571728 (nfsd_mutex){+.+.}-{3:3}, at: write_versions+0x90/0xbb0 fs/nfsd/nfsctl.c:683
2 locks held by syz-executor/12422:
 #0: ffff8880203f9118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf1/0x780 block/bdev.c:911
 #1: ffff888020620468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa9/0xb50 drivers/block/loop.c:1366
3 locks held by syz.4.3977/14274:
 #0: ffff8880212a8870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff888078c50460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8c571728 (nfsd_mutex){+.+.}-{3:3}, at: write_versions+0x90/0xbb0 fs/nfsd/nfsctl.c:683
2 locks held by syz-executor/14436:
 #0: ffff8880203e8518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf1/0x780 block/bdev.c:911
 #1: ffff888147680468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa9/0xb50 drivers/block/loop.c:1366

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 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+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 16001 Comm: syz.0.4452 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:192 [inline]
RIP: 0010:mark_lock+0x66/0x320 kernel/locking/lockdep.c:4569
Code: b6 47 02 24 03 3c 01 bd 09 00 00 00 83 dd 00 41 bc 01 00 00 00 89 e9 41 d3 e4 4d 8d 7e 20 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 22 02 00 00 41 8b 07 41 89 c7 41 81 e7 ff 1f 00 00 c1
RSP: 0000:ffffc90002f1f8a0 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff888028a85940 RCX: 0000000000000003
RDX: 0000000000000003 RSI: ffff888028a86430 RDI: ffff888028a85940
RBP: 0000000000000003 R08: ffffffff8d8b0def R09: 1ffffffff1b161bd
R10: dffffc0000000000 R11: fffffbfff1b161be R12: 0000000000000008
R13: dffffc0000000000 R14: ffff888028a86430 R15: ffff888028a86450
FS:  00005555858c8500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c24da3a CR3: 0000000040b77000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 mark_held_locks kernel/locking/lockdep.c:4193 [inline]
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4211 [inline]
 lockdep_hardirqs_on_prepare+0x237/0x7c0 kernel/locking/lockdep.c:4278
 trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49
 lock_page_memcg+0x1fb/0x440 mm/memcontrol.c:2059
 page_add_file_rmap+0x180/0x930 mm/rmap.c:1219
 do_set_pte+0x3c9/0x530 mm/memory.c:4069
 filemap_map_pages+0xef4/0x1450 mm/filemap.c:3344
 do_fault_around mm/memory.c:4243 [inline]
 do_read_fault mm/memory.c:4258 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x25bb/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f3d2b7278b6
Code: ff 48 83 e8 01 48 89 de bf 01 00 00 00 48 c1 e0 0e 48 c1 ee 06 48 01 c8 48 89 d9 81 e6 ff 3f 00 00 48 c1 e9 03 83 e1 07 d3 e7 <40> 84 bc 06 20 20 00 00 0f 85 20 fe ff ff e9 d4 fd ff ff 0f 1f 80
RSP: 002b:00007ffe394882e0 EFLAGS: 00010202
RAX: 000000110c248000 RBX: ffffffff81ae86b9 RCX: 0000000000000007
RDX: 00000000000006b9 RSI: 0000000000003a1a RDI: 0000000000000080
RBP: 0000000000000000 R08: 00007f3d2bac5000 R09: 00007f3d2bac7000
R10: 0000000081ae86bd R11: 0000000000000002 R12: 00007f3d2badb218
R13: 000000000000000f R14: ffffffff81ae877c R15: 00007f3d2c60a720
 </TASK>