[syzbot] possible deadlock in discov_off
From: syzbot
Date: Mon Oct 03 2022 - 03:49:47 EST
Hello,
syzbot found the following issue on:
HEAD commit: c3e0e1e23c70 Merge tag 'irq_urgent_for_v6.0' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14471d38880000
kernel config: https://syzkaller.appspot.com/x/.config?x=755695d26ad09807
dashboard link: https://syzkaller.appspot.com/bug?extid=f047480b1e906b46a3f4
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.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/67576e43d5c7/disk-c3e0e1e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e568fb42b955/vmlinux-c3e0e1e2.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f047480b1e906b46a3f4@xxxxxxxxxxxxxxxxxxxxxxxxx
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc7-syzkaller-00081-gc3e0e1e23c70 #0 Not tainted
------------------------------------------------------
kworker/u5:5/3650 is trying to acquire lock:
ffff88807606c078 (&hdev->lock){+.+.}-{3:3}, at: discov_off+0x88/0x1a0 net/bluetooth/mgmt.c:1033
but task is already holding lock:
ffffc90003f5fda8 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}:
__flush_work+0x105/0xae0 kernel/workqueue.c:3069
__cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160
mgmt_index_removed+0x218/0x340 net/bluetooth/mgmt.c:8952
hci_unregister_dev+0x34f/0x4e0 net/bluetooth/hci_core.c:2688
vhci_release+0x7c/0xf0 drivers/bluetooth/hci_vhci.c:568
__fput+0x277/0x9d0 fs/file_table.c:320
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xad5/0x29b0 kernel/exit.c:795
do_group_exit+0xd2/0x2f0 kernel/exit.c:925
get_signal+0x238c/0x2610 kernel/signal.c:2857
arch_do_signal_or_restart+0x82/0x2300 arch/x86/kernel/signal.c:869
exit_to_user_mode_loop kernel/entry/common.c:166 [inline]
exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #0 (&hdev->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
discov_off+0x88/0x1a0 net/bluetooth/mgmt.c:1033
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((work_completion)(&(&hdev->discov_off)->work));
lock(&hdev->lock);
lock((work_completion)(&(&hdev->discov_off)->work));
lock(&hdev->lock);
*** DEADLOCK ***
2 locks held by kworker/u5:5/3650:
#0: ffff88807a95e938 ((wq_completion)hci0){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88807a95e938 ((wq_completion)hci0){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff88807a95e938 ((wq_completion)hci0){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff88807a95e938 ((wq_completion)hci0){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff88807a95e938 ((wq_completion)hci0){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff88807a95e938 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc90003f5fda8 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
stack backtrace:
CPU: 0 PID: 3650 Comm: kworker/u5:5 Not tainted 6.0.0-rc7-syzkaller-00081-gc3e0e1e23c70 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Workqueue: hci0 discov_off
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
discov_off+0x88/0x1a0 net/bluetooth/mgmt.c:1033
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
---
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