INFO: task syz-executor:5827 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:24024 pid:5827 tgid:5827 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1347
deactivate_locked_super+0xc1/0x1a0 fs/super.c:473
deactivate_super fs/super.c:506 [inline]
deactivate_super+0xde/0x100 fs/super.c:502
cleanup_mnt+0x225/0x450 fs/namespace.c:1327
task_work_run+0x150/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdf705909f7
RSP: 002b:00007ffec54de498 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fdf705909f7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffec54de550
RBP: 00007ffec54de550 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffec54df5e0
R13: 00007fdf70611d7d R14: 000000000002bf99 R15: 00007ffec54df620
Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
#0: ffffffff8e3cfb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
3 locks held by kworker/1:0/24:
#0: ffff88813ff15948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc900001e7d00 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff8e3cfa40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3820
1 lock held by khungtaskd/31:
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
1 lock held by syz-executor/5815:
2 locks held by syz-executor/5827:
#0: ffff8880536560e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880536560e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880536560e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff8880536560e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e7ed248 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
2 locks held by getty/6348:
#0: ffff88814d29b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000574b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.1.282/7205:
#0: ffffffff9018ebd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7ed248 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b10 fs/nfsd/nfsctl.c:1880
2 locks held by syz-executor/7587:
#0: ffff8880560780e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880560780e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880560780e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff8880560780e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e7ed248 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
3 locks held by kworker/u8:21/9668:
#0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc9001d287d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff8e3cfa40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3820
3 locks held by syz.2.862/10202:
#0: ffff88802ba987f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232
#1: ffff88807c786420 (sb_writers#3){.+.+}-{0:0}, at: do_writev+0x132/0x340 fs/read_write.c:1103
#2: ffffffff8e7ed248 (nfsd_mutex){+.+.}-{4:4}, at: expkey_flush+0x20/0x90 fs/nfsd/export.c:250
1 lock held by syz.5.953/10711:
#0: ffff888035525288 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#0: ffff888035525288 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:661
1 lock held by syz.5.953/10713:
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5824 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline]
RIP: 0010:write_comp_data+0x3c/0x90 kernel/kcov.c:246
Code: 8b 05 88 de e4 11 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 0f 00 75 60 a9 00 00 f0 00 75 59 8b 82 7c 16 00 00 85 c0 74 4f <8b> 82 58 16 00 00 83 f8 03 75 44 48 8b 82 60 16 00 00 8b 92 5c 16
RSP: 0018:ffffc90003a777c8 EFLAGS: 00000246
RAX: 0000000080000001 RBX: ffffc90003a77cb0 RCX: ffffffff820cd22c
RDX: ffff88802f001e40 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000001 R12: 0000000000000001
R13: ffffffffffffffff R14: dffffc0000000000 R15: ffffea00017ebc00
FS: 0000000000000000(0000) GS:ffff888124a0d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8fb4517d60 CR3: 000000000e182000 CR4: 00000000003526f0
Call Trace:
__tlb_remove_folio_pages_size.constprop.0+0x4c/0x560 mm/mmu_gather.c:171
zap_present_folio_ptes mm/memory.c:1657 [inline]
zap_present_ptes mm/memory.c:1710 [inline]
do_zap_pte_range mm/memory.c:1811 [inline]
zap_pte_range mm/memory.c:1855 [inline]
zap_pmd_range mm/memory.c:1947 [inline]
zap_pud_range mm/memory.c:1976 [inline]
zap_p4d_range mm/memory.c:1997 [inline]
unmap_page_range+0x15ca/0x41b0 mm/memory.c:2018
unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:2061
unmap_vmas+0x218/0x470 mm/memory.c:2105
exit_mmap+0x1b2/0xb90 mm/mmap.c:1280
__mmput+0x12a/0x410 kernel/fork.c:1133
mmput+0x62/0x70 kernel/fork.c:1156
exit_mm kernel/exit.c:582 [inline]
do_exit+0x7c7/0x2bf0 kernel/exit.c:954
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
__do_sys_exit_group kernel/exit.c:1118 [inline]
__se_sys_exit_group kernel/exit.c:1116 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1116
x64_sys_call+0x150b/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8fb378f6c9
Code: Unable to access opcode bytes at 0x7f8fb378f69f.
RSP: 002b:00007ffc60714568 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f8fb381385d RCX: 00007f8fb378f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007f8fb381386f R08: 00007ffc60712307 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 000000000004fb5a R15: 00007ffc60714710