syzbot


INFO: task hung in reg_check_chans_work

Status: upstream: reported on 2025/06/17 22:04
Reported-by: syzbot+2e8a009d0669eed02147@syzkaller.appspotmail.com
First crash: 31d, last: 9d12h
Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in reg_check_chans_work 1 10 254d 539d 0/3 auto-obsoleted due to no activity on 2025/02/14 20:30
linux-6.1 INFO: task hung in reg_check_chans_work (2) 1 1 210d 210d 0/3 auto-obsoleted due to no activity on 2025/03/30 18:04
upstream INFO: task hung in reg_check_chans_work (6) wireless 1 C error 129 377d 450d 26/29 fixed on 2024/07/09 19:14
upstream INFO: task hung in reg_check_chans_work (3) wireless 1 60 1322d 1385d 0/29 auto-closed as invalid on 2022/04/03 20:03
linux-4.14 INFO: task hung in reg_check_chans_work 1 1 1167d 1167d 0/1 auto-obsoleted due to no activity on 2022/09/05 08:58
upstream INFO: task hung in reg_check_chans_work (7) wireless 1 C error 610 10h06m 298d 0/29 upstream: reported C repro on 2024/09/23 08:39
upstream INFO: task hung in reg_check_chans_work (4) wireless 1 4 1114d 1117d 0/29 auto-closed as invalid on 2022/09/28 14:08
upstream INFO: task hung in reg_check_chans_work net 1 15 2652d 2711d 0/29 closed as dup on 2018/02/14 15:33
linux-6.1 INFO: task hung in reg_check_chans_work (3) 1 1 103d 103d 0/3 auto-obsoleted due to no activity on 2025/07/15 07:58
android-44 INFO: task hung in reg_check_chans_work 1 18 2624d 2698d 0/2 auto-closed as invalid on 2019/02/22 14:50
android-49 INFO: task hung in reg_check_chans_work 1 18 2623d 2721d 0/3 auto-closed as invalid on 2019/02/22 15:19
linux-6.1 INFO: task hung in reg_check_chans_work 1 3 401d 419d 0/3 auto-obsoleted due to no activity on 2024/09/20 17:51
upstream INFO: task hung in reg_check_chans_work (5) wireless 1 26 628d 757d 0/29 auto-obsoleted due to no activity on 2024/01/08 12:17
upstream INFO: task hung in reg_check_chans_work (2) wireless 1 3 1746d 1755d 0/29 auto-closed as invalid on 2021/01/04 12:48

Sample crash report:
INFO: task kworker/0:4:16434 blocked for more than 143 seconds.
      Not tainted 6.6.96-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:23688 pid:16434 ppid:2      flags:0x00004000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x14e2/0x4580 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 wiphy_lock include/net/cfg80211.h:5777 [inline]
 reg_leave_invalid_chans net/wireless/reg.c:2451 [inline]
 reg_check_chans_work+0x104/0xd70 net/wireless/reg.c:2466
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/0:0/8:
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2f760 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
1 lock held by kcompactd0/32:
3 locks held by kworker/u4:4/58:
2 locks held by kworker/1:2/786:
1 lock held by syslogd/5140:
 #0: ffff888024233148 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:669 [inline]
 #0: ffff888024233148 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x23b/0x650 mm/memory.c:5487
1 lock held by klogd/5147:
 #0: ffff8880235322f8 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:669 [inline]
 #0: ffff8880235322f8 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x23b/0x650 mm/memory.c:5487
2 locks held by udevd/5158:
3 locks held by kworker/1:3/5430:
2 locks held by getty/5544:
 #0: ffff888031f420a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015c72f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5772:
2 locks held by kworker/u4:2/15741:
1 lock held by syz-executor/17973:
 #0: ffff88802cca0308 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_target+0x81/0x230 net/netfilter/x_tables.c:254
1 lock held by syz-executor/17977:
2 locks held by syz-executor/17979:
1 lock held by udevd/18134:
2 locks held by syz.7.3090/18519:
3 locks held by sed/18521:
3 locks held by syz-executor/18530:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.6.96-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 18134 Comm: udevd Not tainted 6.6.96-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__sanitizer_cov_trace_switch+0x4/0x120 kernel/kcov.c:329
Code: 28 4d 39 ca 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 07 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 c3 90 f3 0f 1e fa <48> 8b 06 48 8b 4e 08 48 83 c1 f8 48 c1 c1 3d 48 83 f9 02 7f 1e 48
RSP: 0018:ffffc900046ef310 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff8ed85bba RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8cb9e160 RDI: 0000000000000001
RBP: ffffc900046ef438 R08: ffffc900046ef447 R09: 0000000000000000
R10: ffffc900046ef438 R11: fffff520008dde89 R12: ffffc900046ef3e8
R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffff8ed85bbe
FS:  00007f6f6e98e880(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559258066178 CR3: 00000000285df000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 unwind_next_frame+0x16d9/0x2970 arch/x86/kernel/unwind_orc.c:641
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:128
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 __slab_free+0x35e/0x410 mm/slub.c:3722
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3493 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3500 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 lsm_file_alloc security/security.c:612 [inline]
 security_file_alloc+0x34/0x120 security/security.c:2603
 init_file+0x94/0x1f0 fs/file_table.c:161
 alloc_empty_file+0xb7/0x1d0 fs/file_table.c:210
 path_openat+0x100/0x3190 fs/namei.c:3775
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6f6e2a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffcd37958a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6f6e98e880 RCX: 00007f6f6e2a7407
RDX: 0000000000080241 RSI: 00007ffcd3795e00 RDI: ffffffffffffff9c
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001b6 R11: 0000000000000202 R12: 000055f9ff800dfc
R13: 000055f9ff800dfc R14: 0000000000000001 R15: 000055fa018d6c10
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/09 15:13 linux-6.6.y a5df3a702b2c f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in reg_check_chans_work
2025/06/17 22:03 linux-6.6.y c2603c511feb e77fae15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in reg_check_chans_work
* Struck through repros no longer work on HEAD.