INFO: task syz.4.2032:13273 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2032 state:D stack:27688 pid:13273 tgid:13270 ppid:5861 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 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+0x7e6/0x1350 kernel/locking/mutex.c:760
nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:593
nfsd_umount+0x42/0xd0 fs/nfsd/nfsctl.c:1347
deactivate_locked_super+0xbc/0x130 fs/super.c:473
cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xe9/0x130 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+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc80b98eec9
RSP: 002b:00007fc80c80d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc80bbe6090 RCX: 00007fc80b98eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
RBP: 00007fc80ba11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc80bbe6128 R14: 00007fc80bbe6090 R15: 00007ffdd1980728
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e33d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e33d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5626:
#0: ffff88803430d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz.0.2017/13214:
#0: ffffffff8f7a6390 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e621a08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.4.2032/13273:
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
#1: ffffffff8e621a08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:593
2 locks held by syz.5.2109/13743:
#0: ffffffff8f7a6390 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e621a08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
1 lock held by syz.8.2118/13815:
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by syz.8.2118/13817:
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by syz.8.2118/13819:
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by syz.8.2118/13820:
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff8880292320e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
2 locks held by syz.0.2344/14964:
1 lock held by syz.2.2346/14972:
1 lock held by syz.9.2342/14980:
#0: ffffffff8e342c40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
6 locks held by syz.1.2349/14987:
#0: ffffffff8e3312c0 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:669 [inline]
#0: ffffffff8e3312c0 (console_lock){+.+.}-{0:0}, at: vt_resizex+0x296/0x550 drivers/tty/vt/vt_ioctl.c:700
#1: ffff88823be42e80 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_pan_display+0xbe/0xbd0 drivers/gpu/drm/drm_fb_helper.c:1441
#2: ffff888024e24128 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x20/0x80 drivers/gpu/drm/drm_auth.c:435
#3: ffff88823be42c98 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_locked+0x4c/0x4d0 drivers/gpu/drm/drm_client_modeset.c:1204
#4: ffffc9000ad07210 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0xda/0x760 drivers/gpu/drm/drm_client_modeset.c:1042
#5: ffffc9000ad07238 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_atomic+0xda/0x760 drivers/gpu/drm/drm_client_modeset.c:1042
1 lock held by syz.1.2349/14991:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/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+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5a/0xb0 kernel/rcu/tree.c:751
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 4c 07 7f 00 48 c7 c3 d8 6f c3 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 34 8b 03 65 ff 0d f9 51 1b 11 74 11 83 e0 04 c1 e8 02 5b
RSP: 0018:ffffc90000a08ad8 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff8880b8732fd8 RCX: 542050062cb3fc00
RDX: 0000000000000000 RSI: ffffffff8c03da40 RDI: ffffffff8c03da00
RBP: ffffc90000a08be0 R08: ffffffff8fc36c77 R09: 1ffffffff1f86d8e
R10: dffffc0000000000 R11: fffffbfff1f86d8f R12: 0000000000000010
R13: ffff88801d6a5ac0 R14: ffffffff8ddc7dd8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125afc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c46a8fc CR3: 00000000794a8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000010003 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
trace_sched_set_need_resched_tp+0x3a/0x120 include/trace/events/sched.h:895
__resched_curr+0x1eb/0x3e0 kernel/sched/core.c:1118
resched_curr kernel/sched/core.c:1141 [inline]
wakeup_preempt+0xb6/0x280 kernel/sched/core.c:2210
ttwu_do_activate+0x216/0x870 kernel/sched/core.c:3707
ttwu_queue kernel/sched/core.c:3969 [inline]
try_to_wake_up+0x721/0x12b0 kernel/sched/core.c:4293
hrtimer_wakeup+0x4e/0x60 kernel/time/hrtimer.c:2013
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 71 28 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: 542050062cb3fc00 RBX: ffffffff81971c07 RCX: 542050062cb3fc00
RDX: 0000000000000001 RSI: ffffffff8dba1162 RDI: ffffffff8c03da60
RBP: ffffc90000197f10 R08: ffff8880b8732fdb R09: 1ffff110170e65fb
R10: dffffc0000000000 R11: ffffed10170e65fc R12: ffffffff8fc36c70
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11003ad4b58
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e7/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x147