Re: [syzbot] INFO: task hung in hci_dev_close_sync

[Hillf Danton <hdanton@sina.com>]

On Tue, 03 May 2022 09:59:16 -0700
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    9f9b9a2972eb Add linux-next specific files for 20220502
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1304f300f00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=db7d696bedca61f5
> dashboard link: https://syzkaller.appspot.com/bug?extid=c56f6371c48cad0420f9
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+c56f6371c48cad0420f9@syzkaller.appspotmail.com
> 
> INFO: task kworker/u5:1:3691 blocked for more than 143 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/u5:1    state:D stack:27464 pid: 3691 ppid:     2 flags:0x00004000
> Workqueue: hci4 hci_power_on
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  __flush_work+0x56c/0xb10 kernel/workqueue.c:3098
>  __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3185
>  hci_dev_close_sync+0x8d/0x1150 net/bluetooth/hci_sync.c:4092
>  hci_dev_do_close+0x32/0x70 net/bluetooth/hci_core.c:553
>  hci_power_on+0x1c0/0x630 net/bluetooth/hci_core.c:981
>  process_one_work+0x996/0x1610 kernel/workqueue.c:2289
>  worker_thread+0x665/0x1080 kernel/workqueue.c:2436
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
>  </TASK>
> INFO: task kworker/u5:2:3694 blocked for more than 143 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/u5:2    state:D stack:27688 pid: 3694 ppid:     2 flags:0x00004000
> Workqueue: hci1 hci_power_on
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  __flush_work+0x56c/0xb10 kernel/workqueue.c:3098
>  __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3185
>  hci_dev_close_sync+0x8d/0x1150 net/bluetooth/hci_sync.c:4092
>  hci_dev_do_close+0x32/0x70 net/bluetooth/hci_core.c:553
>  hci_power_on+0x1c0/0x630 net/bluetooth/hci_core.c:981
>  process_one_work+0x996/0x1610 kernel/workqueue.c:2289
>  worker_thread+0x665/0x1080 kernel/workqueue.c:2436
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
>  </TASK>
> INFO: task kworker/u5:3:3696 blocked for more than 143 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/u5:3    state:D stack:27192 pid: 3696 ppid:     2 flags:0x00004000
> Workqueue: hci2 hci_power_on
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  __flush_work+0x56c/0xb10 kernel/workqueue.c:3098
>  __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3185
>  hci_dev_close_sync+0x8d/0x1150 net/bluetooth/hci_sync.c:4092
>  hci_dev_do_close+0x32/0x70 net/bluetooth/hci_core.c:553
>  hci_power_on+0x1c0/0x630 net/bluetooth/hci_core.c:981
>  process_one_work+0x996/0x1610 kernel/workqueue.c:2289
>  worker_thread+0x665/0x1080 kernel/workqueue.c:2436
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
>  </TASK>
> INFO: task kworker/u5:5:5430 blocked for more than 144 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/u5:5    state:D stack:27536 pid: 5430 ppid:     2 flags:0x00004000
> Workqueue: hci0 hci_power_on
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  __flush_work+0x56c/0xb10 kernel/workqueue.c:3098

This is the problem, see below.

>  __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3185
>  hci_dev_close_sync+0x8d/0x1150 net/bluetooth/hci_sync.c:4092
>  hci_dev_do_close+0x32/0x70 net/bluetooth/hci_core.c:553
>  hci_power_on+0x1c0/0x630 net/bluetooth/hci_core.c:981
>  process_one_work+0x996/0x1610 kernel/workqueue.c:2289
>  worker_thread+0x665/0x1080 kernel/workqueue.c:2436
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
>  </TASK>
> INFO: task syz-executor.5:5786 blocked for more than 144 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz-executor.5  state:D stack:28408 pid: 5786 ppid:     1 flags:0x00000000
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  flush_workqueue+0x44e/0x1440 kernel/workqueue.c:2884
>  hci_dev_open+0xdb/0x300 net/bluetooth/hci_core.c:526
>  hci_sock_ioctl+0x62c/0x910 net/bluetooth/hci_sock.c:1027
>  sock_do_ioctl+0xcc/0x230 net/socket.c:1131
>  sock_ioctl+0x2f1/0x640 net/socket.c:1248
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:870 [inline]
>  __se_sys_ioctl fs/ioctl.c:856 [inline]
>  __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f13b1488ea7
> RSP: 002b:00007ffeca7dc868 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007ffeca7dcf28 RCX: 00007f13b1488ea7
> RDX: 0000000000000000 RSI: 00000000400448c9 RDI: 0000000000000003
> RBP: 0000000000000003 R08: 00007f13b0bff700 R09: 00007f13b0bff700
> R10: 00007f13b0bff9d0 R11: 0000000000000246 R12: 0000000000000003
> R13: 00007ffeca7dc9c0 R14: 00007f13b159c9b8 R15: 000000000000000c
>  </TASK>
> INFO: task syz-executor.3:5903 blocked for more than 144 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz-executor.3  state:D stack:28408 pid: 5903 ppid:     1 flags:0x00004000
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  flush_workqueue+0x44e/0x1440 kernel/workqueue.c:2884
>  hci_dev_open+0xdb/0x300 net/bluetooth/hci_core.c:526
>  hci_sock_ioctl+0x62c/0x910 net/bluetooth/hci_sock.c:1027
>  sock_do_ioctl+0xcc/0x230 net/socket.c:1131
>  sock_ioctl+0x2f1/0x640 net/socket.c:1248
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:870 [inline]
>  __se_sys_ioctl fs/ioctl.c:856 [inline]
>  __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7ffbbf688ea7
> RSP: 002b:00007fffc1092908 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fffc1092fc8 RCX: 00007ffbbf688ea7
> RDX: 0000000000000001 RSI: 00000000400448c9 RDI: 0000000000000003
> RBP: 0000000000000003 R08: 00007ffbbedff700 R09: 00007ffbbedff700
> R10: 00007ffbbedff9d0 R11: 0000000000000246 R12: 0000000000000003
> R13: 00007fffc1092a60 R14: 00007ffbbf79c9b8 R15: 000000000000000c
>  </TASK>
> INFO: task syz-executor.2:6048 blocked for more than 144 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz-executor.2  state:D stack:28408 pid: 6048 ppid:     1 flags:0x00004000
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  flush_workqueue+0x44e/0x1440 kernel/workqueue.c:2884
>  hci_dev_open+0xdb/0x300 net/bluetooth/hci_core.c:526
>  hci_sock_ioctl+0x62c/0x910 net/bluetooth/hci_sock.c:1027
>  sock_do_ioctl+0xcc/0x230 net/socket.c:1131
>  sock_ioctl+0x2f1/0x640 net/socket.c:1248
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:870 [inline]
>  __se_sys_ioctl fs/ioctl.c:856 [inline]
>  __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7ff9c0e88ea7
> RSP: 002b:00007ffed3e82ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007ffed3e83598 RCX: 00007ff9c0e88ea7
> RDX: 0000000000000004 RSI: 00000000400448c9 RDI: 0000000000000003
> RBP: 0000000000000003 R08: 00007ff9c05ff700 R09: 00007ff9c05ff700
> R10: 00007ff9c05ff9d0 R11: 0000000000000246 R12: 0000000000000003
> R13: 00007ffed3e83030 R14: 00007ff9c0f9c9b8 R15: 000000000000000c
>  </TASK>
> INFO: task syz-executor.0:6305 blocked for more than 145 seconds.
>       Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz-executor.0  state:D stack:28408 pid: 6305 ppid:     1 flags:0x00000000
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5106 [inline]
>  __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6421
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6493
>  schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1883
>  do_wait_for_common kernel/sched/completion.c:85 [inline]
>  __wait_for_common+0x378/0x530 kernel/sched/completion.c:106
>  flush_workqueue+0x44e/0x1440 kernel/workqueue.c:2884
>  hci_dev_open+0xdb/0x300 net/bluetooth/hci_core.c:526
>  hci_sock_ioctl+0x62c/0x910 net/bluetooth/hci_sock.c:1027
>  sock_do_ioctl+0xcc/0x230 net/socket.c:1131
>  sock_ioctl+0x2f1/0x640 net/socket.c:1248
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:870 [inline]
>  __se_sys_ioctl fs/ioctl.c:856 [inline]
>  __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7fe7a4488ea7
> RSP: 002b:00007ffcc64117a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007ffcc6411e68 RCX: 00007fe7a4488ea7
> RDX: 0000000000000002 RSI: 00000000400448c9 RDI: 0000000000000003
> RBP: 0000000000000003 R08: 00007fe7a3bff700 R09: 00007fe7a3bff700
> R10: 00007fe7a3bff9d0 R11: 0000000000000246 R12: 0000000000000003
> R13: 00007ffcc6411900 R14: 00007fe7a459c9b8 R15: 000000000000000c
>  </TASK>
> 
> Showing all locks held in the system:
> 1 lock held by rcu_tasks_kthre/12:
>  #0: ffffffff8bd84cd0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:502
> 1 lock held by rcu_tasks_trace/13:
>  #0: ffffffff8bd84950 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:502
> 1 lock held by khungtaskd/29:
>  #0: ffffffff8bd85820 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491
> 2 locks held by getty/3356:
>  #0: ffff88814bb09098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
>  #1: ffffc90002ce62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xe50/0x13c0 drivers/tty/n_tty.c:2118
> 3 locks held by kworker/u5:1/3691:
>  #0: ffff88802520a938 ((wq_completion)hci4){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff88802520a938 ((wq_completion)hci4){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
>  #0: ffff88802520a938 ((wq_completion)hci4){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
>  #0: ffff88802520a938 ((wq_completion)hci4){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
>  #0: ffff88802520a938 ((wq_completion)hci4){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
>  #0: ffff88802520a938 ((wq_completion)hci4){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
>  #1: ffffc90002f5fda8 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
>  #2: ffff88801e529048 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x2a/0x70 net/bluetooth/hci_core.c:551
> 3 locks held by kworker/u5:2/3694:
>  #0: ffff88807eb0f138 ((wq_completion)hci1){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff88807eb0f138 ((wq_completion)hci1){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
>  #0: ffff88807eb0f138 ((wq_completion)hci1){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
>  #0: ffff88807eb0f138 ((wq_completion)hci1){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
>  #0: ffff88807eb0f138 ((wq_completion)hci1){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
>  #0: ffff88807eb0f138 ((wq_completion)hci1){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
>  #1: ffffc9000307fda8 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
>  #2: ffff88801e165048 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x2a/0x70 net/bluetooth/hci_core.c:551
> 3 locks held by kworker/u5:3/3696:
>  #0: ffff88807ad37938 ((wq_completion)hci2){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff88807ad37938 ((wq_completion)hci2){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
>  #0: ffff88807ad37938 ((wq_completion)hci2){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
>  #0: ffff88807ad37938 ((wq_completion)hci2){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
>  #0: ffff88807ad37938 ((wq_completion)hci2){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
>  #0: ffff88807ad37938 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
>  #1: ffffc9000309fda8 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
>  #2: ffff88807d985048 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x2a/0x70 net/bluetooth/hci_core.c:551
> 3 locks held by kworker/u5:5/5430:
>  #0: ffff88805b8c0938 ((wq_completion)hci0){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff88805b8c0938 ((wq_completion)hci0){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
>  #0: ffff88805b8c0938 ((wq_completion)hci0){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
>  #0: ffff88805b8c0938 ((wq_completion)hci0){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
>  #0: ffff88805b8c0938 ((wq_completion)hci0){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
>  #0: ffff88805b8c0938 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
>  #1: ffffc90002e3fda8 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
>  #2: ffff888075741048 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x2a/0x70 net/bluetooth/hci_core.c:551
> 
> =============================================
> 
> NMI backtrace for cpu 0
> CPU: 0 PID: 29 Comm: khungtaskd Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
>  nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
>  nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
>  trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
>  check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
>  watchdog+0xc22/0xf90 kernel/hung_task.c:378
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
>  </TASK>
> Sending NMI from CPU 0 to CPUs 1:
> NMI backtrace for cpu 1
> CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 5.18.0-rc5-next-20220502-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Workqueue: events_unbound toggle_allocation_gate
> RIP: 0010:__lock_acquire+0xd51/0x5660 kernel/locking/lockdep.c:5063
> Code: 03 0f b6 04 02 84 c0 74 0d 3c 03 7f 09 48 8b 3c 24 e8 63 78 69 00 41 8b 85 58 0a 00 00 83 c0 01 83 f8 2f 41 89 85 58 0a 00 00 <0f> 87 eb 0b 00 00 3b 05 53 e2 1e 0e 41 be 01 00 00 00 0f 86 c8 00
> RSP: 0018:ffffc900000d7748 EFLAGS: 00000097
> RAX: 0000000000000006 RBX: ffffffff8f3c6c00 RCX: ffffffff815ddcee
> RDX: 1ffff110021e1c5b RSI: 0000000000000001 RDI: ffffffff8f3c6c18
> RBP: 000000000000f5e5 R08: 0000000000000000 R09: ffffffff9007b897
> R10: fffffbfff200f712 R11: 0000000000000001 R12: ffff888010f0e3a8
> R13: ffff888010f0d880 R14: 0000000000000000 R15: d4985ce4c67f0360
> FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000c001d7d000 CR3: 000000000ba8e000 CR4: 00000000003506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  lock_acquire kernel/locking/lockdep.c:5665 [inline]
>  lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5630
>  __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
>  _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
>  spin_lock include/linux/spinlock.h:354 [inline]
>  __get_locked_pte+0x154/0x270 mm/memory.c:1830
>  get_locked_pte include/linux/mm.h:2127 [inline]
>  __text_poke+0x1ae/0x8c0 arch/x86/kernel/alternative.c:1038
>  text_poke arch/x86/kernel/alternative.c:1121 [inline]
>  text_poke_bp_batch+0x433/0x6b0 arch/x86/kernel/alternative.c:1436
>  text_poke_flush arch/x86/kernel/alternative.c:1542 [inline]
>  text_poke_flush arch/x86/kernel/alternative.c:1539 [inline]
>  text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1549
>  arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
>  jump_label_update+0x32f/0x410 kernel/jump_label.c:830
>  static_key_disable_cpuslocked+0x152/0x1b0 kernel/jump_label.c:207
>  static_key_disable+0x16/0x20 kernel/jump_label.c:215
>  toggle_allocation_gate mm/kfence/core.c:809 [inline]
>  toggle_allocation_gate+0x183/0x390 mm/kfence/core.c:787
>  process_one_work+0x996/0x1610 kernel/workqueue.c:2289
>  worker_thread+0x665/0x1080 kernel/workqueue.c:2436
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
>  </TASK>
> ----------------
> Code disassembly (best guess):
>    0:	03 0f                	add    (%rdi),%ecx
>    2:	b6 04                	mov    $0x4,%dh
>    4:	02 84 c0 74 0d 3c 03 	add    0x33c0d74(%rax,%rax,8),%al
>    b:	7f 09                	jg     0x16
>    d:	48 8b 3c 24          	mov    (%rsp),%rdi
>   11:	e8 63 78 69 00       	callq  0x697879
>   16:	41 8b 85 58 0a 00 00 	mov    0xa58(%r13),%eax
>   1d:	83 c0 01             	add    $0x1,%eax
>   20:	83 f8 2f             	cmp    $0x2f,%eax
>   23:	41 89 85 58 0a 00 00 	mov    %eax,0xa58(%r13)
> * 2a:	0f 87 eb 0b 00 00    	ja     0xc1b <-- trapping instruction
>   30:	3b 05 53 e2 1e 0e    	cmp    0xe1ee253(%rip),%eax        # 0xe1ee289
>   36:	41 be 01 00 00 00    	mov    $0x1,%r14d
>   3c:	0f                   	.byte 0xf
>   3d:	86 c8                	xchg   %cl,%al
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> 

Given the call trace reported,

	process_one_work
	  lock_map_acquire(&pwq->wq->lockdep_map);
	  lock_map_acquire(&lockdep_map);
	  hci_power_on
	    hci_dev_do_close
	      hci_req_sync_lock(hdev);
	      hci_dev_close_sync(hdev);
	        cancel_work_sync(&hdev->power_on);
		  __cancel_work_timer()
		    __flush_work(work, true);
			if (!from_cancel) {
				lock_map_acquire(&work->lockdep_map);
				lock_map_release(&work->lockdep_map);
			}
	      hci_req_sync_unlock(hdev);


syzbot should have been able to catch cancel_work_sync() in work context
by checking lockdep_map in __flush_work() for both flush and cancel.

Hillf

--- y/kernel/workqueue.c
+++ x/kernel/workqueue.c
@@ -3075,10 +3075,10 @@ static bool __flush_work(struct work_str
 	if (WARN_ON(!work->func))
 		return false;
 
-	if (!from_cancel) {
+	//if (!from_cancel) {
 		lock_map_acquire(&work->lockdep_map);
 		lock_map_release(&work->lockdep_map);
-	}
+	//}
 
 	if (start_flush_work(work, &barr, from_cancel)) {
 		wait_for_completion(&barr.done);