INFO: task syz.0.5839:24205 blocked for more than 143 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.5839 state:D stack:28488 pid:24205 tgid:24204 ppid:5822 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe6/0x5fa0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1353
deactivate_locked_super+0xc1/0x1b0 fs/super.c:474
deactivate_super fs/super.c:507 [inline]
deactivate_super+0xe7/0x110 fs/super.c:503
cleanup_mnt+0x21f/0x450 fs/namespace.c:1318
task_work_run+0x150/0x240 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
exit_to_user_mode_loop+0x100/0x4b0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ea/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdbe6b9aeb9
RSP: 002b:00007fdbe7980028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007fdbe6e15fa0 RCX: 00007fdbe6b9aeb9
RDX: 0000200000000100 RSI: 00002000000000c0 RDI: 0000000000000000
RBP: 00007fdbe6c08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdbe6e16038 R14: 00007fdbe6e15fa0 R15: 00007ffe00b10978
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:8/3547:
2 locks held by sshd-session/5811:
2 locks held by syz-executor/6366:
2 locks held by syz.4.1557/10586:
2 locks held by syz.3.5749/23870:
#0: ffffffff904a2bd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
2 locks held by syz-executor/23907:
2 locks held by syz.0.5839/24205:
#0: ffff8880571b40e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880571b40e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880571b40e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff8880571b40e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
3 locks held by kworker/0:3/24557:
#0: ffff88813fe15948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc900050f7c98 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff8e5ef7c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816
3 locks held by kworker/u8:7/25328:
#0: ffff88801c29f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc90018387c98 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff8e5ef7c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816
2 locks held by syz.2.6134/25359:
#0: ffff888049c180e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888049c180e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888049c180e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff888049c180e0 (&type->s_umount_key#58){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503
#1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
1 lock held by syz.5.6310/26143:
2 locks held by syz.5.6311/26150:
1 lock held by syz.7.6319/26154:
#0: ffffffff8e5ef8f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline]
watchdog+0xcc3/0xfe0 kernel/hung_task.c:515
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1166 Comm: kworker/u8:6 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:insn_get_prefixes+0x900/0x15e0 arch/x86/lib/insn.c:201
Code: 93 f6 48 8b 04 24 41 83 f6 06 44 88 70 51 e9 49 fc ff ff e8 f2 1f 93 f6 48 8b 04 24 48 8d 78 0c 48 b8 00 00 00 00 00 fc ff df <48> 89 fa 48 c1 ea 03 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84
RSP: 0018:ffffc90003f1f6d0 EFLAGS: 00000293
RAX: dffffc0000000000 RBX: 000000000000000f RCX: ffffffff8b733135
RDX: ffff8880280c8000 RSI: ffffffff8b732e6e RDI: ffffc90003f1f90c
RBP: ffffffff8263ba8b R08: 0000000000000005 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 00000000000000e9 R14: 0000000000816000 R15: 00000000000000e9
FS: 0000000000000000(0000) GS:ffff8881245e2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b333f0ff8 CR3: 000000000e392000 CR4: 00000000003526f0
Call Trace:
insn_get_opcode+0x82/0x11b0 arch/x86/lib/insn.c:285
insn_get_modrm+0x84/0x790 arch/x86/lib/insn.c:391
insn_get_sib arch/x86/lib/insn.c:466 [inline]
insn_get_displacement+0x2f9/0x960 arch/x86/lib/insn.c:507
insn_get_immediate+0x84/0x1e00 arch/x86/lib/insn.c:673
insn_get_length arch/x86/lib/insn.c:745 [inline]
insn_decode+0x21d/0x320 arch/x86/lib/insn.c:784
arch_jump_entry_size+0xb6/0x150 arch/x86/kernel/jump_label.c:24
__jump_label_patch+0x85/0x3e0 arch/x86/kernel/jump_label.c:45
arch_jump_label_transform_queue+0x7e/0x120 arch/x86/kernel/jump_label.c:137
__jump_label_update+0xd7/0x380 kernel/jump_label.c:513
jump_label_update+0x37a/0x550 kernel/jump_label.c:919
static_key_disable_cpuslocked+0x162/0x1c0 kernel/jump_label.c:240
static_key_disable+0x1a/0x20 kernel/jump_label.c:248
toggle_allocation_gate mm/kfence/core.c:901 [inline]
toggle_allocation_gate+0x149/0x2d0 mm/kfence/core.c:886
process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246