INFO: task syz-executor:4275 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22224 pid:4275  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
 nfsd_shutdown_threads+0x4f/0x1a0 fs/nfsd/nfssvc.c:633
 nfsd_umount+0x3e/0xc0 fs/nfsd/nfsctl.c:1409
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x471/0x4f0 fs/namespace.c:1191
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f278039f397
RSP: 002b:00007ffeb69ab238 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f2780434474 RCX: 00007f278039f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeb69ab2f0
RBP: 00007ffeb69ab2f0 R08: 00007ffeb69ac2f0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb69ac380
R13: 00007f2780434474 R14: 0000000000025a0f R15: 00007ffeb69ac3c0
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e5b0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2edd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
3 locks held by kworker/u4:2/31:
2 locks held by getty/4031:
 #0: ffff88814d5bf098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by syz-executor/4275:
 #0: ffff888077f5a0e0 (&type->s_umount_key#51){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffffffff8cdcd108 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x4f/0x1a0 fs/nfsd/nfssvc.c:633
1 lock held by udevd/4391:
 #0: ffff8880b8e3acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
3 locks held by syz.0.44/4627:
 #0: ffff88807c0d9c68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
 #1: ffff88807ca60460 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
 #2: ffffffff8cdcd108 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
2 locks held by syz.5.333/5892:
 #0: ffff88804d8fa0e0 (&type->s_umount_key#51){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffffffff8cdcd108 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x4f/0x1a0 fs/nfsd/nfssvc.c:633
1 lock held by syz.1.745/8027:
1 lock held by dhcpcd-run-hook/8155:
 #0: ffff8880b8f3acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
1 lock held by syz.8.760/8164:
 #0: ffffffff8cb337c0 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x5e0 kernel/rcu/tree.c:4023
2 locks held by dhcpcd-run-hook/8195:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 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+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8169 Comm: syz.8.760 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:384 [inline]
RIP: 0010:__rcu_read_unlock+0x2e/0xd0 kernel/rcu/tree_plugin.h:423
Code: 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3d 35 6d 95 7e 48 8d 9f 3c 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 48 ff 0b 75 1d 4c 8d b7 40 04 00 00 4c 89 f0 48 c1 e8 03
RSP: 0018:ffffc9000539f3c0 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffff8880254aa23c RCX: 55387a978e30e600
RDX: 0000000000000000 RSI: ffffffff8adf6400 RDI: ffff8880254a9e00
RBP: ffff8880531cf438 R08: ffffea00017e8347 R09: 1ffffd40002fd068
R10: dffffc0000000000 R11: fffff940002fd069 R12: 1ffff11004a95447
R13: 0000000000000000 R14: dffffc0000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556f0fd52138 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 __folio_memcg_unlock+0xea/0x110 mm/memcontrol.c:2151
 page_remove_rmap+0x7f5/0xef0 mm/rmap.c:1462
 zap_pte_range mm/memory.c:1451 [inline]
 zap_pmd_range mm/memory.c:1572 [inline]
 zap_pud_range mm/memory.c:1601 [inline]
 zap_p4d_range mm/memory.c:1622 [inline]
 unmap_page_range+0x10db/0x25b0 mm/memory.c:1643
 unmap_vmas+0x260/0x390 mm/memory.c:1728
 exit_mmap+0x20d/0x970 mm/mmap.c:3250
 __mmput+0x118/0x3a0 kernel/fork.c:1210
 exit_mm+0x24d/0x350 kernel/exit.c:572
 do_exit+0x958/0x2570 kernel/exit.c:874
 do_group_exit+0x229/0x2e0 kernel/exit.c:1030
 get_signal+0x1259/0x1340 kernel/signal.c:2880
 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efd2659e159
Code: Unable to access opcode bytes at 0x7efd2659e12f.
RSP: 002b:00007efd27522028 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: fffffffffffffe00 RBX: 00007efd26826090 RCX: 00007efd2659e159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007efd26635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efd26826128 R14: 00007efd26826090 R15: 00007ffd186583a8
 </TASK>