syzbot


INFO: task hung in hci_cmd_sync_clear (2)

Status: upstream: reported syz repro on 2025/01/26 06:48
Reported-by: syzbot+bb555a2060a46486fa24@syzkaller.appspotmail.com
First crash: 10d, last: 10d
Bug presence (1)
Date Name Commit Repro Result
2025/01/27 upstream (ToT) 9c5968db9e62 C Failed due to an error; will retry later
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in hci_cmd_sync_clear bluetooth 4 901d 1048d 0/28 auto-obsoleted due to no activity on 2022/11/16 14:10
linux-6.1 INFO: task hung in hci_cmd_sync_clear 1 325d 325d 0/3 auto-obsoleted due to no activity on 2024/06/24 21:55
upstream INFO: task hung in hci_cmd_sync_clear (2) bluetooth 15 316d 722d 0/28 auto-obsoleted due to no activity on 2024/06/23 16:01
upstream INFO: task hung in hci_cmd_sync_clear (3) bluetooth syz done 4 4d04h 88d 0/28 upstream: reported syz repro on 2024/11/09 06:00

Sample crash report:
INFO: task syz-executor:4410 blocked for more than 143 seconds.
      Not tainted 6.1.127-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:4410  ppid:1      flags:0x0000000d
Call trace:
 __switch_to+0x308/0x598 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 schedule_timeout+0xb8/0x344 kernel/time/timer.c:1941
 do_wait_for_common+0x30c/0x468 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __flush_work+0x12c/0x1c0 kernel/workqueue.c:3076
 __cancel_work_timer+0x3ec/0x548 kernel/workqueue.c:3163
 cancel_work_sync+0x24/0x38 kernel/workqueue.c:3199
 hci_cmd_sync_clear+0x3c/0x1f8 net/bluetooth/hci_sync.c:668
 hci_unregister_dev+0x174/0x4c4 net/bluetooth/hci_core.c:2702
 vhci_release+0x7c/0xcc drivers/bluetooth/hci_vhci.c:573
 __fput+0x1c8/0x7c8 fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x240/0x2f0 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x550/0x1a84 kernel/exit.c:871
 do_group_exit+0x194/0x22c kernel/exit.c:1021
 get_signal+0x14a0/0x158c kernel/signal.c:2871
 do_signal arch/arm64/kernel/signal.c:1076 [inline]
 do_notify_resume+0x388/0x2cb8 arch/arm64/kernel/signal.c:1129
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task syz-executor:5067 blocked for more than 143 seconds.
      Not tainted 6.1.127-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:5067  ppid:1      flags:0x0000000d
Call trace:
 __switch_to+0x308/0x598 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 schedule_timeout+0xb8/0x344 kernel/time/timer.c:1941
 do_wait_for_common+0x30c/0x468 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __flush_work+0x12c/0x1c0 kernel/workqueue.c:3076
 __cancel_work_timer+0x3ec/0x548 kernel/workqueue.c:3163
 cancel_work_sync+0x24/0x38 kernel/workqueue.c:3199
 hci_cmd_sync_clear+0x3c/0x1f8 net/bluetooth/hci_sync.c:668
 hci_unregister_dev+0x174/0x4c4 net/bluetooth/hci_core.c:2702
 vhci_release+0x7c/0xcc drivers/bluetooth/hci_vhci.c:573
 __fput+0x1c8/0x7c8 fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x240/0x2f0 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x550/0x1a84 kernel/exit.c:871
 do_group_exit+0x194/0x22c kernel/exit.c:1021
 get_signal+0x14a0/0x158c kernel/signal.c:2871
 do_signal arch/arm64/kernel/signal.c:1076 [inline]
 do_notify_resume+0x388/0x2cb8 arch/arm64/kernel/signal.c:1129
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015c65530 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015c65d30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015c65360 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
3 locks held by kworker/u5:0/47:
 #0: ffff0000de619138 ((wq_completion)hci6){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff80001d787c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000cd1450b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
2 locks held by getty/4054:
 #0: ffff0000d6829098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001d8102f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2198
3 locks held by kworker/u5:1/4381:
 #0: ffff0000c326d938 ((wq_completion)hci1){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021477c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000cad290b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:2/4383:
 #0: ffff0000cc54f138 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021497c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000ee57d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:3/5069:
 #0: ffff0000dea25938 ((wq_completion)hci9){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021a87c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000f0ed50b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:4/5070:
 #0: ffff0000cd363138 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021a97c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000c3f010b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:5/5683:
 #0: ffff0000db897938 ((wq_completion)hci8){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000219b7c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000d4cf10b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:6/5803:
 #0: ffff0000db54c938 ((wq_completion)hci3){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800022377c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000d42190b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:7/6374:
 #0: ffff0000c2e06138 ((wq_completion)hci4){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021d07c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000cde050b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:8/6944:
 #0: ffff0000d375b938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021717c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000ddffd0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:9/7558:
 #0: ffff0000f3751138 ((wq_completion)hci11){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800025907c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000f2e390b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:10/8177:
 #0: ffff0000dd455938 ((wq_completion)hci7){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800025727c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000de5c50b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
2 locks held by kworker/u4:5/8771:
3 locks held by kworker/u5:11/8796:
 #0: ffff0000cf69b138 ((wq_completion)hci10){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800024fd7c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000dbd950b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:12/9397:
 #0: ffff0000db45c938 ((wq_completion)hci12){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800024d77c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000d8b410b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:13/10017:
 #0: ffff0000db45e138 ((wq_completion)hci12#2){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800024cb7c20 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000d8b40078 (&hdev->lock){+.+.}-{3:3}, at: hci_le_create_big_complete_evt+0xd0/0x868 net/bluetooth/hci_event.c:6835
3 locks held by kworker/u5:14/10637:
 #0: ffff0000d4205938 ((wq_completion)hci13){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000246f7c20 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000f0f8d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x194/0x34c net/bluetooth/hci_sync.c:321
3 locks held by kworker/u5:15/11237:
 #0: ffff0000d38cd938 ((wq_completion)hci13#2){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000241b7c20 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0000f0f8c078 (&hdev->lock){+.+.}-{3:3}, at: hci_le_create_big_complete_evt+0xd0/0x868 net/bluetooth/hci_event.c:6835
1 lock held by syz-executor/12734:

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


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/26 06:47 linux-6.1.y 75cefdf153f5 9fbd772e .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in hci_cmd_sync_clear
* Struck through repros no longer work on HEAD.