[v6.6] INFO: task hung in hci_release_dev

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 924b4a879cbb Linux 6.6.142
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1600b4ae580000
kernel config: https://syzkaller.appspot.com/x/.config?x=90249d2d52c08134
dashboard link: https://syzkaller.appspot.com/bug?extid=617ce8f0648afb890cf5
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bd13425862f1/disk-924b4a87.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eaa5de9e440b/vmlinux-924b4a87.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a9aa3293c15/bzImage-924b4a87.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+617ce8...@syzkaller.appspotmail.com

INFO: task kworker/u5:1:5088 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u5:1 state:D stack:25768 pid:5088 ppid:2 flags:0x00004000
Workqueue: hci0 hci_error_reset
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0xc1/0x2d0 kernel/time/timer.c:2144
do_wait_for_common kernel/sched/completion.c:95 [inline]
__wait_for_common kernel/sched/completion.c:116 [inline]
wait_for_common kernel/sched/completion.c:127 [inline]
wait_for_completion+0x2cb/0x5b0 kernel/sched/completion.c:148
__flush_workqueue+0x664/0x13d0 kernel/workqueue.c:3260
drain_workqueue+0xd3/0x380 kernel/workqueue.c:3373
destroy_workqueue+0xc4/0xf20 kernel/workqueue.c:4882
hci_release_dev+0xe2/0x1430 net/bluetooth/hci_core.c:2744
bt_host_release+0x82/0x90 net/bluetooth/hci_sysfs.c:87
device_release+0xbc/0x1e0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x221/0x460 lib/kobject.c:737
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
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>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a6/0x3e0 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+0xf3d/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: 23099 Comm: cmp Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:do_strnlen_user lib/strnlen_user.c:-1 [inline]
RIP: 0010:strnlen_user+0x91/0x1c0 lib/strnlen_user.c:113
Code: fd 4c 89 f8 4c 01 f0 0f 88 24 01 00 00 4c 39 f0 0f 82 1b 01 00 00 48 89 1c 24 0f 01 cb 0f ae e8 4c 89 f0 48 83 e0 f8 4c 8b 28 <45> 89 f4 41 83 e4 07 42 8d 0c e5 00 00 00 00 48 c7 c0 ff ff ff ff
RSP: 0018:ffffc900037a79a0 EFLAGS: 00040206
RAX: 00007fffb458cc90 RBX: 0000000000020000 RCX: ffff888053155a00
RDX: 0000000000000000 RSI: 00007fffb458cc95 RDI: 00007fffb45acc95
RBP: ffffc900037a7af0 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd
R10: dffffc0000000000 R11: fffffbfff1d16cce R12: 00007fffb45acc95
R13: 706d630000000000 R14: 00007fffb458cc95 R15: 0000000000020000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffb458b549 CR3: 000000006b608000 CR4: 00000000003506e0
DR0: 0000000000000009 DR1: 00000000000000c9 DR2: 00000000000000f3
DR3: 00000000000000c0 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
create_elf_tables+0xfad/0x1550 fs/binfmt_elf.c:321
load_elf_binary+0x1d4c/0x2860 fs/binfmt_elf.c:1313
search_binary_handler fs/exec.c:1775 [inline]
exec_binprm fs/exec.c:1817 [inline]
bprm_execve+0xb08/0x1700 fs/exec.c:1892
do_execveat_common+0x51b/0x6c0 fs/exec.c:1998
do_execve fs/exec.c:2072 [inline]
__do_sys_execve fs/exec.c:2148 [inline]
__se_sys_execve fs/exec.c:2143 [inline]
__x64_sys_execve+0x92/0xa0 fs/exec.c:2143
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f37535ef107
Code: Unable to access opcode bytes at 0x7f37535ef0dd.
RSP: 002b:00007fffaa109218 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 0000562986c64298 RCX: 00007f37535ef107
RDX: 0000562986c60038 RSI: 0000562986c64298 RDI: 0000562986c600e8
RBP: 0000562986c600e8 R08: 00007fffaa10ed02 R09: 0000000000000210
R10: 0000000000000230 R11: 0000000000000246 R12: 0000562986c60038
R13: 00007f37537b4e8b R14: 0000562986c60038 R15: 0000000000000000
</TASK>


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