INFO: task syz.5.1199:9784 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.5.1199 state:D stack:27888 pid:9784 tgid:9780 ppid:5607 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d4/0x5630 kernel/sched/core.c:7239
__schedule_loop kernel/sched/core.c:7316 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7331
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7388
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
nfsd_nrthreads+0x5b/0x320 fs/nfsd/nfssvc.c:245
write_threads+0x1fe/0x5a0 fs/nfsd/nfsctl.c:438
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112
vfs_write+0x296/0xba0 fs/read_write.c:685
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6f07b9e0d9
RSP: 002b:00007f6f08a80028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6f07e26090 RCX: 00007f6f07b9e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f6f07c35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6f07e26128 R14: 00007f6f07e26090 R15: 00007ffdfa79e5e8
Showing all locks held in the system:
locks held by khungtaskd/31: 1, last CPU#1:
#0: ffffffff8eb5a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8eb5a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8eb5a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6793
locks held by kworker/u9:1/4923: 3, on CPU#1:
#0: ffff888025f62140 ((wq_completion)hci3){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888025f62140 ((wq_completion)hci3){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405
#1: ffffc9000fd3fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000fd3fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405
#2: ffff88807e99cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1cb/0x3f0 net/bluetooth/hci_sync.c:331
locks held by getty/5362: 2, on CPU#0:
#0: ffff8880350ff0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/u8:14/5884: 2, on CPU#0:
#0: ffff88801e315940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801e315940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405
#1: ffffc9000462fc40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000462fc40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405
locks held by syz.5.1199/9781: 3, on CPU#1:
#0: ffff88807ab39b30 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888069262460 (sb_writers#39){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
#1: ffff888069262460 (sb_writers#39){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860
locks held by syz.5.1199/9784: 3, on CPU#0:
#0: ffff888031959970 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888069262460 (sb_writers#39){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
#1: ffff888069262460 (sb_writers#39){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8fbe0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nrthreads+0x5b/0x320 fs/nfsd/nfssvc.c:245
locks held by syz-executor/10144: 1, on CPU#0:
#0: ffffffff8eb603e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8eb603e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
locks held by syz.7.1794/12244: 1, on CPU#0:
#0: ffff888076a052c0 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1025 [inline]
#0: ffff888076a052c0 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:734
locks held by dhcpcd-run-hook/12290: 2, last CPU#1:
#0: ffff8880b863b2e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb2/0x160 kernel/sched/core.c:675
#1: ffff8880b8724408 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5617 Comm: kworker/1:3 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events free_obj_work
RIP: 0010:lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
RIP: 0010:lock_release+0xa1/0x3c0 kernel/locking/lockdep.c:5906
Code: 41 83 bf a4 0b 00 00 00 0f 85 f7 01 00 00 49 81 3e 20 b5 2f 94 0f 84 ea 01 00 00 9c 5b fa 48 c7 c7 57 b3 24 8e e8 3f fa 31 0a <65> ff 05 30 8c cb 11 c7 44 24 24 01 00 00 00 83 3d a9 15 b5 0e 00
RSP: 0018:ffffc90002f2f518 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000206 RCX: 0000000000000046
RDX: ffffc90002f2f601 RSI: ffffffff8e24b357 RDI: ffffffff8c4bdd80
RBP: 1ffffffff21f8901 R08: ffffc90002f2fa30 R09: ffffc90002f2f678
R10: dffffc0000000000 R11: fffff520005e5ed1 R12: ffffc90002f28000
R13: ffffffff8177710f R14: ffffffff8eb5a0e0 R15: ffff88807b131f40
FS: 0000000000000000(0000) GS:ffff88812503f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9b231ef9b8 CR3: 0000000061651000 CR4: 0000000000350ef0
Call Trace:
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6504
free_object_list lib/debugobjects.c:326 [inline]
free_obj_work+0x352/0x480 lib/debugobjects.c:530
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa88/0x14c0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245