INFO: task syz.0.2003:10810 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2003 state:D stack:27656 pid:10810 tgid:10809 ppid:5608 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7376
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccb/0x1bd0 kernel/locking/mutex.c:821
write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a0199e559
RSP: 002b:00007f5a02886028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5a01c25fa0 RCX: 00007f5a0199e559
RDX: 0000000000000001 RSI: 0000200000000440 RDI: 0000000000000004
RBP: 00007f5a01a35ab8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a01c26038 R14: 00007f5a01c25fa0 R15: 00007ffc6c44ab08
Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#0:
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by syz-executor/5597: 2, on CPU#0:
#0: ffff88802e3360e8 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88802e3360e8 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88802e3360e8 (&type->s_umount_key#73){++++}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
#0: ffff88802e3360e8 (&type->s_umount_key#73){++++}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
#1: ffffffff90289d60 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by kworker/0:6/5790: 9, last CPU#0:
#0: ffff888024eb3d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc900049ffd08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
#2: ffff88802bee91d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802bee91d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bb/0x4420 drivers/usb/core/hub.c:5917
#3: ffff88823beee9d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#3: ffff88823beee9d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#4: ffff88802cd721a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff88802cd721a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#5: ffff88807ea31a58 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#5: ffff88807ea31a58 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#6: ffff88807c6a45c0 (&led_cdev->led_access){+.+.}-{4:4}, at: led_classdev_register_ext+0x48c/0x990 drivers/leds/led-class.c:554
#7: ffffffff92278ba0 (uevent_sock_mutex){+.+.}-{4:4}, at: uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
#7: ffffffff92278ba0 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
#7: ffffffff92278ba0 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:611
#8: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#8: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#8: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: sock_def_readable+0x90/0x600 net/core/sock.c:3665
locks held by getty/8007: 2, on CPU#1:
#0: ffff88802a9940a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90003f452e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz.3.1312/8868: 3, on CPU#0:
#0: ffff88807b5ae7f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff8880264fc460 (sb_writers#14){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff90289d60 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.0.2003/10810: 3, on CPU#1:
#0: ffff88807e4cd970 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88805472a460 (sb_writers#14){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff90289d60 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.4.3599/14758: 5, last CPU#0:
#0: ffff888074b85270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff8880506da460 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffff888034380880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
#3: ffff8880222ff4b8 (kn->active#131){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#3: ffff8880222ff4b8 (kn->active#131){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
#4: ffffffff9c9d2240 (resize mutex#2){+.+.}-{4:4}, at: set_max_huge_pages mm/hugetlb.c:3792 [inline]
#4: ffffffff9c9d2240 (resize mutex#2){+.+.}-{4:4}, at: __nr_hugepages_store_common+0x10a/0x1950 mm/hugetlb.c:4113
locks held by syz.9.3651/14940: 2, last CPU#0:
#0: ffff88802b794080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff88802b794080 (&mm->mmap_lock){++++}-{4:4}, at: madvise_lock+0xec/0x240 mm/madvise.c:1789
#1: ffff88805ba327a8 (&anon_vma->rwsem){++++}-{4:4}, at: folio_lock_anon_vma_read+0x348/0xe30 mm/rmap.c:655
locks held by fido_id/14939: 1, last CPU#0:
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: lock_vma_under_rcu+0x25/0x590 mm/mmap_lock.c:303
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245