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: 69d, last: 4d08h
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 292d 576d 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 248d 248d 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 415d 488d 26/29 fixed on 2024/07/09 19:14
upstream INFO: task hung in reg_check_chans_work (3) wireless 1 60 1360d 1423d 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 1205d 1205d 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 679 16h35m 336d 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 1152d 1154d 0/29 auto-closed as invalid on 2022/09/28 14:08
upstream INFO: task hung in reg_check_chans_work net 1 15 2690d 2749d 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 141d 141d 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 2662d 2735d 0/2 auto-closed as invalid on 2019/02/22 14:50
android-49 INFO: task hung in reg_check_chans_work 1 18 2661d 2759d 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 439d 456d 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 666d 795d 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 1784d 1793d 0/29 auto-closed as invalid on 2021/01/04 12:48

Sample crash report:
INFO: task kworker/1:3:1192 blocked for more than 143 seconds.
      Not tainted 6.6.102-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:3     state:D stack:21960 pid:1192  ppid:2      flags:0x00004000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __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 pool_workqueue_/3:
 #0: ffffffff8cd35bb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
 #0: ffffffff8cd35bb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004
1 lock held by khungtaskd/28:
 #0: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/1:1/42:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90000b2fd00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90000b2fd00 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
1 lock held by klogd/5148:
2 locks held by udevd/5159:
2 locks held by getty/5547:
 #0: ffff88802dcb40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000327b2f0 (&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:
1 lock held by syz-executor/5781:
 #0: ffff88814c41a308 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x54/0x3e0 net/netfilter/x_tables.c:1242
3 locks held by syz-executor/5787:
1 lock held by syz-executor/5788:
 #0: ffffffff8dfbba48 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8dfbba48 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511
4 locks held by udevd/7129:
3 locks held by dhcpcd-run-hook/12085:
3 locks held by kworker/0:6/12084:
2 locks held by syz-executor/12089:
2 locks held by kworker/0:7/12093:
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc9000523fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc9000523fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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: 12089 Comm: syz-executor Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:unwind_next_frame+0x1754/0x2970 arch/x86/kernel/unwind_orc.c:648
Code: 00 00 41 80 3f 01 0f 85 8b 04 00 00 e8 25 d1 4a 00 e9 ad 04 00 00 4c 8d 73 02 48 83 c3 03 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 d9 10 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000ba473d8 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffffffff8ed9157d RCX: 0000000000000003
RDX: ffffffff813ab999 RSI: ffffffff8cb9e5a0 RDI: 0000000000000001
RBP: ffffc9000ba474f8 R08: ffff8880290b9e00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc9000ba474a8
R13: dffffc0000000000 R14: ffffffff8ed9157c R15: ffffffff8ed9157e
FS:  000055557a93e500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6aef4e56e8 CR3: 00000001a1684000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 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
 discard_slab mm/slub.c:2122 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2662
 put_cpu_partial+0x17c/0x250 mm/slub.c:2738
 __slab_free+0x31d/0x410 mm/slub.c:3686
 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
 vm_area_alloc+0x24/0x1d0 kernel/fork.c:486
 __mmap_region mm/mmap.c:2766 [inline]
 mmap_region+0xbe6/0x1f80 mm/mmap.c:2937
 do_mmap+0x8d1/0xfd0 mm/mmap.c:1381
 vm_mmap_pgoff+0x1c0/0x400 mm/util.c:556
 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: 0033:0x7f6aee78ec23
Code: f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 41 89 ca 41 f7 c1 ff 0f 00 00 75 14 b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 25 c3 0f 1f 40 00 48 c7 c0 a8 ff ff ff 64 c7
RSP: 002b:00007ffdffc1bca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6aee78ec23
RDX: 0000000000000007 RSI: 0000000001000000 RDI: 0000200000000000
RBP: 0000000000000002 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000100022 R11: 0000000000000246 R12: 0000200000000000
R13: 00007ffdffc1bf98 R14: 0000000000000009 R15: 0000000000000009
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/21 14:29 linux-6.6.y bb9c90ab9c5a 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in reg_check_chans_work
2025/08/20 09:40 linux-6.6.y bb9c90ab9c5a 79512909 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in reg_check_chans_work
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.