2024-04-26 13:40:08

by syzbot

[permalink] [raw]
Subject: [syzbot] [bluetooth?] possible deadlock in hci_dev_do_close (2)

Hello,

syzbot found the following issue on:

HEAD commit: bb7a2467e6be Add linux-next specific files for 20240426
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1337aaa0980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6a0288262dd108
dashboard link: https://syzkaller.appspot.com/bug?extid=c55f7bc8d4809b2bad59
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5175af7dda64/disk-bb7a2467.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70db0462e868/vmlinux-bb7a2467.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3217fb825698/bzImage-bb7a2467.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

Bluetooth: hci6: Opcode 0x0c1a failed: -110
Bluetooth: hci6: Error when powering off device on rfkill (-110)
======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc5-next-20240426-syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:3/5122 is trying to acquire lock:
ffff88805c0888d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
ffff88805c0888d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
ffff88805c0888d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4113 [inline]
ffff88805c0888d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: __flush_work+0xe6/0xd00 kernel/workqueue.c:4172

but task is already holding lock:
ffff88805c089060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x28/0x90 net/bluetooth/hci_core.c:559

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&hdev->req_lock){+.+.}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
hci_cmd_sync_work+0x1ec/0x400 net/bluetooth/hci_sync.c:309
process_one_work kernel/workqueue.c:3222 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3303
worker_thread+0x86d/0xd70 kernel/workqueue.c:3384
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
touch_work_lockdep_map kernel/workqueue.c:3885 [inline]
start_flush_work kernel/workqueue.c:4139 [inline]
__flush_work+0x73c/0xd00 kernel/workqueue.c:4172
__cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4322
hci_cmd_sync_clear+0x30/0x220 net/bluetooth/hci_sync.c:588
hci_dev_close_sync+0xbae/0x1060 net/bluetooth/hci_sync.c:5188
hci_dev_do_close+0x30/0x90 net/bluetooth/hci_core.c:561
hci_rfkill_set_block+0x232/0x300 net/bluetooth/hci_core.c:992
rfkill_set_block+0x1f1/0x440 net/rfkill/core.c:346
rfkill_epo+0x84/0x180 net/rfkill/core.c:466
__rfkill_handle_global_op net/rfkill/input.c:60 [inline]
rfkill_op_handler+0x121/0x280 net/rfkill/input.c:108
process_one_work kernel/workqueue.c:3222 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3303
worker_thread+0x86d/0xd70 kernel/workqueue.c:3384
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&hdev->req_lock);
lock((work_completion)(&hdev->cmd_sync_work));
lock(&hdev->req_lock);
lock((work_completion)(&hdev->cmd_sync_work));

*** DEADLOCK ***

5 locks held by kworker/0:3/5122:
#0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3197 [inline]
#0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3303
#1: ffffc9000387fd00 ((rfkill_op_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3198 [inline]
#1: ffffc9000387fd00 ((rfkill_op_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3303
#2: ffffffff8f8b13e8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_epo+0x4f/0x180 net/rfkill/core.c:462
#3: ffff88805c089060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x28/0x90 net/bluetooth/hci_core.c:559
#4: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#4: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#4: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: start_flush_work kernel/workqueue.c:4113 [inline]
#4: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: __flush_work+0xe6/0xd00 kernel/workqueue.c:4172

stack backtrace:
CPU: 0 PID: 5122 Comm: kworker/0:3 Not tainted 6.9.0-rc5-next-20240426-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events rfkill_op_handler
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
touch_work_lockdep_map kernel/workqueue.c:3885 [inline]
start_flush_work kernel/workqueue.c:4139 [inline]
__flush_work+0x73c/0xd00 kernel/workqueue.c:4172
__cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4322
hci_cmd_sync_clear+0x30/0x220 net/bluetooth/hci_sync.c:588
hci_dev_close_sync+0xbae/0x1060 net/bluetooth/hci_sync.c:5188
hci_dev_do_close+0x30/0x90 net/bluetooth/hci_core.c:561
hci_rfkill_set_block+0x232/0x300 net/bluetooth/hci_core.c:992
rfkill_set_block+0x1f1/0x440 net/rfkill/core.c:346
rfkill_epo+0x84/0x180 net/rfkill/core.c:466
__rfkill_handle_global_op net/rfkill/input.c:60 [inline]
rfkill_op_handler+0x121/0x280 net/rfkill/input.c:108
process_one_work kernel/workqueue.c:3222 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3303
worker_thread+0x86d/0xd70 kernel/workqueue.c:3384
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>


---
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2024-04-28 22:35:38

by syzbot

[permalink] [raw]
Subject: Re: [syzbot] [bluetooth?] possible deadlock in hci_dev_do_close (2)

syzbot has found a reproducer for the following issue on:

HEAD commit: bb7a2467e6be Add linux-next specific files for 20240426
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16b60228980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6a0288262dd108
dashboard link: https://syzkaller.appspot.com/bug?extid=c55f7bc8d4809b2bad59
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1590bcf8980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1349ee9b180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5175af7dda64/disk-bb7a2467.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70db0462e868/vmlinux-bb7a2467.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3217fb825698/bzImage-bb7a2467.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

Bluetooth: hci0: Opcode 0x0c1a failed: -110
Bluetooth: hci0: Error when powering off device on rfkill (-110)
======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc5-next-20240426-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor143/5093 is trying to acquire lock:
ffff88807643c8d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
ffff88807643c8d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
ffff88807643c8d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4113 [inline]
ffff88807643c8d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: __flush_work+0xe6/0xd00 kernel/workqueue.c:4172

but task is already holding lock:
ffff88807643d060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x28/0x90 net/bluetooth/hci_core.c:559

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&hdev->req_lock){+.+.}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
hci_cmd_sync_work+0x1ec/0x400 net/bluetooth/hci_sync.c:309
process_one_work kernel/workqueue.c:3222 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3303
worker_thread+0x86d/0xd70 kernel/workqueue.c:3384
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
touch_work_lockdep_map kernel/workqueue.c:3885 [inline]
start_flush_work kernel/workqueue.c:4139 [inline]
__flush_work+0x73c/0xd00 kernel/workqueue.c:4172
__cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4322
hci_cmd_sync_clear+0x30/0x220 net/bluetooth/hci_sync.c:588
hci_dev_close_sync+0xbae/0x1060 net/bluetooth/hci_sync.c:5188
hci_dev_do_close+0x30/0x90 net/bluetooth/hci_core.c:561
hci_rfkill_set_block+0x232/0x300 net/bluetooth/hci_core.c:992
rfkill_set_block+0x1f1/0x440 net/rfkill/core.c:346
rfkill_fop_write+0x5bb/0x790 net/rfkill/core.c:1305
do_loop_readv_writev fs/read_write.c:764 [inline]
vfs_writev+0x733/0xbe0 fs/read_write.c:973
do_writev+0x1b1/0x350 fs/read_write.c:1018
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&hdev->req_lock);
lock((work_completion)(&hdev->cmd_sync_work));
lock(&hdev->req_lock);
lock((work_completion)(&hdev->cmd_sync_work));

*** DEADLOCK ***

3 locks held by syz-executor143/5093:
#0: ffffffff8f8b13e8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x1a9/0x790 net/rfkill/core.c:1297
#1: ffff88807643d060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x28/0x90 net/bluetooth/hci_core.c:559
#2: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#2: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#2: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: start_flush_work kernel/workqueue.c:4113 [inline]
#2: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: __flush_work+0xe6/0xd00 kernel/workqueue.c:4172

stack backtrace:
CPU: 0 PID: 5093 Comm: syz-executor143 Not tainted 6.9.0-rc5-next-20240426-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
touch_work_lockdep_map kernel/workqueue.c:3885 [inline]
start_flush_work kernel/workqueue.c:4139 [inline]
__flush_work+0x73c/0xd00 kernel/workqueue.c:4172
__cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4322
hci_cmd_sync_clear+0x30/0x220 net/bluetooth/hci_sync.c:588
hci_dev_close_sync+0xbae/0x1060 net/bluetooth/hci_sync.c:5188
hci_dev_do_close+0x30/0x90 net/bluetooth/hci_core.c:561
hci_rfkill_set_block+0x232/0x300 net/bluetooth/hci_core.c:992
rfkill_set_block+0x1f1/0x440 net/rfkill/core.c:346
rfkill_fop_write+0x5bb/0x790 net/rfkill/core.c:1305
do_loop_readv_writev fs/read_write.c:764 [inline]
vfs_writev+0x733/0xbe0 fs/read_write.c:973
do_writev+0x1b1/0x350 fs/read_write.c:1018
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22b080b5d9
Code: 48 83 c4 28 c3 e8 47 1d 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff7aee1ff8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f22b085b468 RCX: 00007f22b080b5d9
RDX: 0000000000000001 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00007fff7aee20f0 R08: 00007f2200000001 R09: 00007f2200000001
R10: 00007f2200000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fff7aee20c0 R14: 0000000000000001 R15: 00007fff7aee20f0
</TASK>


---
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