syzbot


INFO: task hung in rfkill_unregister (2)

Status: upstream: reported on 2025/11/29 03:40
Reported-by: syzbot+50a333b456c2736e51d0@syzkaller.appspotmail.com
First crash: 45d, last: 10d
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in rfkill_unregister wireless 1 2 1504d 1506d 0/29 auto-closed as invalid on 2022/01/29 14:25
linux-4.14 INFO: task hung in rfkill_unregister 1 1 2067d 2067d 0/1 auto-closed as invalid on 2020/09/13 12:44
linux-6.1 INFO: task hung in rfkill_unregister 1 12 208d 635d 0/3 auto-obsoleted due to no activity on 2025/09/26 06:02
upstream INFO: task hung in rfkill_unregister (2) wireless 1 2 1325d 1379d 0/29 auto-closed as invalid on 2022/08/27 03:13
linux-5.15 INFO: task hung in rfkill_unregister 1 1 301d 301d 0/3 auto-obsoleted due to no activity on 2025/06/25 15:22
upstream INFO: task hung in rfkill_unregister (3) net nfc 1 C 622 11d 950d 0/29 upstream: reported C repro on 2023/06/07 09:58

Sample crash report:
INFO: task syz-executor:4269 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:21888 pid:4269  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 rfkill_unregister+0xc4/0x220 net/rfkill/core.c:1130
 hci_unregister_dev+0x35c/0x4f0 net/bluetooth/hci_core.c:2722
 vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:573
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x93e/0x2400 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7feb6fb85897
RSP: 002b:00007ffd9f9d4540 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 00000000000000e3 RCX: 00007feb6fb85897
RDX: 0000000040000000 RSI: 00007ffd9f9d45ac RDI: 00000000ffffffff
RBP: 00007ffd9f9d45ac R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000041
R13: 0000555580735590 R14: 0000000000028d2a R15: 00007ffd9f9d4600
 </TASK>
INFO: task kworker/1:10:5598 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:10    state:D stack:22400 pid:5598  ppid:2      flags:0x00004000
Workqueue: events rfkill_global_led_trigger_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 rfkill_global_led_trigger_worker+0x23/0xc0 net/rfkill/core.c:181
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task syz.0.260:5807 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.260       state:D stack:23872 pid:5807  ppid:4269   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 rfkill_unregister+0xc4/0x220 net/rfkill/core.c:1130
 nfc_unregister_device+0x92/0x290 net/nfc/core.c:1167
 virtual_ncidev_close+0x55/0x90 drivers/nfc/virtual_ncidev.c:170
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x93e/0x2400 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7feb6fb8f749
RSP: 002b:00007feb709ea038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 000000000000001c RBX: 00007feb6fde5fa0 RCX: 00007feb6fb8f749
RDX: 0000000000000000 RSI: 0000200000000140 RDI: 000000000000000d
RBP: 00007feb6fc13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feb6fde6038 R14: 00007feb6fde5fa0 R15: 00007ffd9f9d41e8
 </TASK>
INFO: task syz.5.273:5882 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.273       state:D stack:25600 pid:5882  ppid:4621   flags:0x00024004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 device_lock include/linux/device.h:840 [inline]
 nfc_dev_down net/nfc/core.c:143 [inline]
 nfc_rfkill_set_block+0x4c/0x2d0 net/nfc/core.c:179
 rfkill_set_block+0x1c6/0x420 net/rfkill/core.c:345
 rfkill_fop_write+0x458/0x560 net/rfkill/core.c:1286
 vfs_write+0x2c4/0x960 fs/read_write.c:582
 ksys_write+0x143/0x240 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc25998f749
RSP: 002b:00007fc25a78d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc259be5fa0 RCX: 00007fc25998f749
RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000003
RBP: 00007fc259a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc259be6038 R14: 00007fc259be5fa0 R15: 00007ffd9f622a58
 </TASK>
INFO: task syz.4.298:6056 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.298       state:D stack:27904 pid:6056  ppid:4282   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 rfkill_fop_open+0x12b/0x680 net/rfkill/core.c:1163
 misc_open+0x31f/0x390 drivers/char/misc.c:145
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x25c6/0x2e70 fs/namei.c:3791
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
 do_sys_openat2+0x142/0x490 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd51bd8f749
RSP: 002b:00007fd51cb99038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd51bfe5fa0 RCX: 00007fd51bd8f749
RDX: 0000000000000801 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007fd51be13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd51bfe6038 R14: 00007fd51bfe5fa0 R15: 00007fff95fbaf98
 </TASK>
INFO: task syz-executor:6086 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:26912 pid:6086  ppid:1      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 misc_open+0x55/0x390 drivers/char/misc.c:107
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x25c6/0x2e70 fs/namei.c:3791
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
 do_sys_openat2+0x142/0x490 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f108dd8df11
RSP: 002b:00007ffce96c52d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f108dd8df11
RDX: 0000000000000002 RSI: 00007f108de149b7 RDI: 00000000ffffff9c
RBP: 00007f108de149b7 R08: 0000000000000000 R09: 00007f108eb1d6c0
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffce96c56a8 R15: 0000000000000000
 </TASK>
INFO: task syz.6.312:6139 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.312       state:D stack:27904 pid:6139  ppid:4787   flags:0x00024004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 misc_open+0x55/0x390 drivers/char/misc.c:107
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x25c6/0x2e70 fs/namei.c:3791
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
 do_sys_openat2+0x142/0x490 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa0a258f749
RSP: 002b:00007fa0a3414038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa0a27e5fa0 RCX: 00007fa0a258f749
RDX: 0000000000000002 RSI: 0000200000000300 RDI: ffffffffffffff9c
RBP: 00007fa0a2613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa0a27e6038 R14: 00007fa0a27e5fa0 R15: 00007ffdb9d87ef8
 </TASK>
INFO: task syz.3.313:6144 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.313       state:D stack:27904 pid:6144  ppid:4277   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 misc_open+0x55/0x390 drivers/char/misc.c:107
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x25c6/0x2e70 fs/namei.c:3791
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
 do_sys_openat2+0x142/0x490 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fef6938f749
RSP: 002b:00007fef6a24d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fef695e5fa0 RCX: 00007fef6938f749
RDX: 0000000000042182 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007fef69413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fef695e6038 R14: 00007fef695e5fa0 R15: 00007ffc68f0ac08
 </TASK>
INFO: task syz-executor:6149 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:26912 pid:6149  ppid:1      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 misc_open+0x55/0x390 drivers/char/misc.c:107
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x25c6/0x2e70 fs/namei.c:3791
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
 do_sys_openat2+0x142/0x490 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f65d738df11
RSP: 002b:00007ffd224b1600 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f65d738df11
RDX: 0000000000000002 RSI: 00007f65d74149b7 RDI: 00000000ffffff9c
RBP: 00007f65d74149b7 R08: 0000000000000000 R09: 00007f65d811d6c0
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffd224b19d8 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92bab0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8c92c2d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
1 lock held by klogd/3625:
 #0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545
2 locks held by getty/4031:
 #0: ffff88814d496098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by syz-executor/4269:
 #0: ffffffff8ddf7488 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_unregister+0xc4/0x220 net/rfkill/core.c:1130
2 locks held by kworker/u4:5/4355:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004257d00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by kworker/u4:6/4359:
 #0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545
 #1: ffff8880b8f27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x312/0x6d0 kernel/sched/psi.c:987
3 locks held by kworker/1:10/5598:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003b37d00 ((work_completion)(&rfkill_global_led_trigger_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8ddf7488 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_global_led_trigger_worker+0x23/0xc0 net/rfkill/core.c:181
2 locks held by syz.0.260/5807:
 #0: ffff88807c1fd100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
 #0: ffff88807c1fd100 (&dev->mutex){....}-{3:3}, at: nfc_unregister_device+0x5f/0x290 net/nfc/core.c:1165
 #1: ffffffff8ddf7488 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_unregister+0xc4/0x220 net/rfkill/core.c:1130
2 locks held by syz.5.273/5882:
 #0: ffffffff8ddf7488 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x19e/0x560 net/rfkill/core.c:1278
 #1: ffff88807c1fd100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
 #1: ffff88807c1fd100 (&dev->mutex){....}-{3:3}, at: nfc_dev_down net/nfc/core.c:143 [inline]
 #1: ffff88807c1fd100 (&dev->mutex){....}-{3:3}, at: nfc_rfkill_set_block+0x4c/0x2d0 net/nfc/core.c:179
2 locks held by syz.4.298/6056:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
 #1: ffffffff8ddf7488 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_open+0x12b/0x680 net/rfkill/core.c:1163
1 lock held by syz-executor/6086:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz.6.312/6139:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz.3.313/6144:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6149:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6226:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6229:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6230:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6236:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6238:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6244:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6246:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6248:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6254:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6256:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6262:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6264:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107
1 lock held by syz-executor/6266:
 #0: ffffffff8d09da68 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x55/0x390 drivers/char/misc.c:107

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 46 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13
Code: 60 79 9c 8c 4c 89 f6 e8 cd 38 1e fa e9 6e ff ff ff 00 00 cc cc 00 00 cc cc 48 c7 c7 c0 f8 be 8a 48 c7 c6 00 f9 be 8a eb 00 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24
RSP: 0018:ffffc90000b778d8 EFLAGS: 00000046
RAX: 0000000080000000 RBX: ffffffff8a1a7b0f RCX: 000000000001ec70
RDX: 0000000000000001 RSI: ffffffff8a6c0620 RDI: ffffffff8abef920
RBP: ffffc90000b779b8 R08: dffffc0000000000 R09: ffffc90000b77a40
R10: fffff5200016ef52 R11: 1ffff9200016ef48 R12: dffffc0000000000
R13: 1ffffffff18c1e40 R14: 0000000000000a06 R15: 1ffff9200016ef24
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055672e097498 CR3: 000000000c68e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lockdep_hardirqs_off+0xa7/0x100 kernel/locking/lockdep.c:4400
 trace_hardirqs_off+0xe/0x40 kernel/trace/trace_preemptirq.c:76
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
 _raw_spin_lock_irqsave+0x7f/0xf0 kernel/locking/spinlock.c:162
 __debug_object_init+0x5f/0x420 lib/debugobjects.c:621
 init_timer_on_stack_key kernel/time/timer.c:805 [inline]
 schedule_timeout+0x105/0x280 kernel/time/timer.c:2166
 toggle_allocation_gate+0x247/0x430 mm/kfence/core.c:812
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/10 01:49 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in rfkill_unregister
2026/01/02 10:54 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in rfkill_unregister
2026/01/01 00:51 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in rfkill_unregister
2025/12/07 14:10 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in rfkill_unregister
2025/11/29 03:39 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in rfkill_unregister
* Struck through repros no longer work on HEAD.