[v6.1] possible deadlock in sco_conn_del

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syzbot

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Mar 13, 2023, 3:51:43 PM3/13/23
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 6449a0ba6843 Linux 6.1.19
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14b2ca88c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ed8b3ec03e8c126
dashboard link: https://syzkaller.appspot.com/bug?extid=5b0d22db545d622669cf
compiler: Debian clang version 15.0.7, 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/0ad616da3180/disk-6449a0ba.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/42677a30acb3/vmlinux-6449a0ba.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2e21fe35d03d/bzImage-6449a0ba.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5b0d22...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.1.19-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/3675 is trying to acquire lock:
ffff8880323bc130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1721 [inline]
ffff8880323bc130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197

but task is already holding lock:
ffffffff8e1e2e68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1789 [inline]
ffffffff8e1e2e68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x210 net/bluetooth/hci_conn.c:2440

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
hci_connect_cfm include/net/bluetooth/hci_core.h:1774 [inline]
hci_remote_features_evt+0x671/0xaa0 net/bluetooth/hci_event.c:3758
hci_event_func net/bluetooth/hci_event.c:7475 [inline]
hci_event_packet+0x96c/0x1360 net/bluetooth/hci_event.c:7527
hci_rx_work+0x40d/0xa80 net/bluetooth/hci_core.c:4043
process_one_work+0x909/0x1380 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

-> #1 (&hdev->lock){+.+.}-{3:3}:
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
sco_sock_connect+0x181/0x8d0 net/bluetooth/sco.c:593
__sys_connect_file net/socket.c:1976 [inline]
__sys_connect+0x2c9/0x300 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x76/0x80 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
lock_sock_nested+0x44/0x100 net/core/sock.c:3457
lock_sock include/net/sock.h:1721 [inline]
sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197
hci_disconn_cfm include/net/bluetooth/hci_core.h:1792 [inline]
hci_conn_hash_flush+0x10d/0x210 net/bluetooth/hci_conn.c:2440
hci_dev_close_sync+0xa2d/0x1000 net/bluetooth/hci_sync.c:4832
hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
hci_unregister_dev+0x1c6/0x470 net/bluetooth/hci_core.c:2702
vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:568
__fput+0x3b7/0x890 fs/file_table.c:320
task_work_run+0x246/0x300 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x6fb/0x2300 kernel/exit.c:869
do_group_exit+0x202/0x2b0 kernel/exit.c:1019
get_signal+0x16f7/0x17d0 kernel/signal.c:2858
arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:869
exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x60/0x2d0 kernel/entry/common.c:296
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(hci_cb_list_lock);
lock(&hdev->lock);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

3 locks held by syz-executor.1/3675:
#0: ffff888077551028 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline]
#0: ffff888077551028 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1be/0x470 net/bluetooth/hci_core.c:2702
#1: ffff888077550078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x445/0x1000 net/bluetooth/hci_sync.c:4819
#2: ffffffff8e1e2e68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1789 [inline]
#2: ffffffff8e1e2e68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x210 net/bluetooth/hci_conn.c:2440

stack backtrace:
CPU: 1 PID: 3675 Comm: syz-executor.1 Not tainted 6.1.19-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
lock_sock_nested+0x44/0x100 net/core/sock.c:3457
lock_sock include/net/sock.h:1721 [inline]
sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197
hci_disconn_cfm include/net/bluetooth/hci_core.h:1792 [inline]
hci_conn_hash_flush+0x10d/0x210 net/bluetooth/hci_conn.c:2440
hci_dev_close_sync+0xa2d/0x1000 net/bluetooth/hci_sync.c:4832
hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
hci_unregister_dev+0x1c6/0x470 net/bluetooth/hci_core.c:2702
vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:568
__fput+0x3b7/0x890 fs/file_table.c:320
task_work_run+0x246/0x300 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x6fb/0x2300 kernel/exit.c:869
do_group_exit+0x202/0x2b0 kernel/exit.c:1019
get_signal+0x16f7/0x17d0 kernel/signal.c:2858
arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:869
exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x60/0x2d0 kernel/entry/common.c:296
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f794528d567
Code: Unable to access opcode bytes at 0x7f794528d53d.
RSP: 002b:00007ffd603608f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: fffffffffffffff4 RBX: 000000000000002a RCX: 00007f794528d567
RDX: 00007ffd603609cd RSI: 000000000000000a RDI: 00007ffd603609c0
RBP: 00007ffd603609c0 R08: 00000000ffffffff R09: 00007ffd60360790
R10: 0000555556eb6853 R11: 0000000000000246 R12: 00007f79452e6b24
R13: 00007ffd60361a80 R14: 0000555556eb6810 R15: 00007ffd60361ac0
</TASK>


---
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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

syzbot

unread,
Mar 14, 2023, 4:01:00 PM3/14/23
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 2ddbd0f967b3 Linux 5.15.102
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1160d90cc80000
kernel config: https://syzkaller.appspot.com/x/.config?x=fec083380faceb1e
dashboard link: https://syzkaller.appspot.com/bug?extid=af5adc68f211c2849598
compiler: Debian clang version 15.0.7, 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/156d2aa91f3c/disk-2ddbd0f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0e97f5be5fb/vmlinux-2ddbd0f9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/20d0a55a041d/bzImage-2ddbd0f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+af5adc...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.15.102-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/10491 is trying to acquire lock:
ffff88803103d120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1649 [inline]
ffff88803103d120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x104/0x300 net/bluetooth/sco.c:196

but task is already holding lock:
ffffffff8db22d68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
ffffffff8db22d68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x210 net/bluetooth/hci_conn.c:1610

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
hci_connect_cfm include/net/bluetooth/hci_core.h:1503 [inline]
hci_remote_features_evt+0x6d1/0xb50 net/bluetooth/hci_event.c:3323
hci_event_packet+0x6da/0x1480 net/bluetooth/hci_event.c:6376
hci_rx_work+0x240/0x7d0 net/bluetooth/hci_core.c:5153
process_one_work+0x90d/0x1270 kernel/workqueue.c:2306
worker_thread+0xaca/0x1280 kernel/workqueue.c:2453
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 <unknown>:298

-> #1 (&hdev->lock){+.+.}-{3:3}:
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
sco_sock_connect+0x181/0x8c0 net/bluetooth/sco.c:587
__sys_connect_file net/socket.c:1899 [inline]
__sys_connect+0x38b/0x410 net/socket.c:1916
__do_sys_connect net/socket.c:1926 [inline]
__se_sys_connect net/socket.c:1923 [inline]
__x64_sys_connect+0x76/0x80 net/socket.c:1923
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
lock_sock_nested+0x44/0x100 net/core/sock.c:3216
lock_sock include/net/sock.h:1649 [inline]
sco_conn_del+0x104/0x300 net/bluetooth/sco.c:196
hci_disconn_cfm include/net/bluetooth/hci_core.h:1521 [inline]
hci_conn_hash_flush+0x10d/0x210 net/bluetooth/hci_conn.c:1610
hci_dev_do_close+0x9f6/0x1000 net/bluetooth/hci_core.c:1795
hci_unregister_dev+0x2a7/0x510 net/bluetooth/hci_core.c:4033
vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:342
__fput+0x3bf/0x890 fs/file_table.c:280
task_work_run+0x129/0x1a0 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0x6a3/0x2480 kernel/exit.c:872
do_group_exit+0x144/0x310 kernel/exit.c:994
__do_sys_exit_group kernel/exit.c:1005 [inline]
__se_sys_exit_group kernel/exit.c:1003 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1003
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

Chain exists of:
sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(hci_cb_list_lock);
lock(&hdev->lock);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

3 locks held by syz-executor.0/10491:
#0: ffff888030940ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5e/0x1000 net/bluetooth/hci_core.c:1737
#1: ffff888030940078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x42c/0x1000 net/bluetooth/hci_core.c:1782
#2: ffffffff8db22d68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
#2: ffffffff8db22d68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x210 net/bluetooth/hci_conn.c:1610

stack backtrace:
CPU: 1 PID: 10491 Comm: syz-executor.0 Not tainted 5.15.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
lock_acquire+0x1ff/0x570 kernel/locking/lockdep.c:5622
lock_sock_nested+0x44/0x100 net/core/sock.c:3216
lock_sock include/net/sock.h:1649 [inline]
sco_conn_del+0x104/0x300 net/bluetooth/sco.c:196
hci_disconn_cfm include/net/bluetooth/hci_core.h:1521 [inline]
hci_conn_hash_flush+0x10d/0x210 net/bluetooth/hci_conn.c:1610
hci_dev_do_close+0x9f6/0x1000 net/bluetooth/hci_core.c:1795
hci_unregister_dev+0x2a7/0x510 net/bluetooth/hci_core.c:4033
vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:342
__fput+0x3bf/0x890 fs/file_table.c:280
task_work_run+0x129/0x1a0 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0x6a3/0x2480 kernel/exit.c:872
do_group_exit+0x144/0x310 kernel/exit.c:994
__do_sys_exit_group kernel/exit.c:1005 [inline]
__se_sys_exit_group kernel/exit.c:1003 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1003
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe490fe20f9
Code: Unable to access opcode bytes at RIP 0x7fe490fe20cf.
RSP: 002b:00007ffe41349628 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007ffe413497d0 RCX: 00007fe490fe20f9
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000025 R09: 00007ffe413497d0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe49103db0a
R13: 000000000000001c R14: 0000000000000001 R15: 00007ffe41349810

syzbot

unread,
May 14, 2023, 6:13:51 PM5/14/23
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: b0ece631f84a Linux 5.15.111
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1013891a280000
kernel config: https://syzkaller.appspot.com/x/.config?x=db3750b003ff805e
dashboard link: https://syzkaller.appspot.com/bug?extid=af5adc68f211c2849598
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12db9e16280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11186b1a280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eded75b6c3f9/disk-b0ece631.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/20e5ae802010/vmlinux-b0ece631.xz
kernel image: https://storage.googleapis.com/syzbot-assets/05d665c869f3/Image-b0ece631.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+af5adc...@syzkaller.appspotmail.com

cgroup: fork rejected by pids controller in /syz3
======================================================
WARNING: possible circular locking dependency detected
5.15.111-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor343/3976 is trying to acquire lock:
ffff0000d7352120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1649 [inline]
ffff0000d7352120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0xf0/0x4cc net/bluetooth/sco.c:196

but task is already holding lock:
ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x208 net/bluetooth/hci_conn.c:1610

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
hci_connect_cfm include/net/bluetooth/hci_core.h:1503 [inline]
hci_remote_features_evt+0x480/0x928 net/bluetooth/hci_event.c:3323
hci_event_packet+0x5d4/0x1258 net/bluetooth/hci_event.c:6376
hci_rx_work+0x1d0/0x6d0 net/bluetooth/hci_core.c:5153
process_one_work+0x790/0x11b8 kernel/workqueue.c:2307
worker_thread+0x910/0x1034 kernel/workqueue.c:2454
kthread+0x37c/0x45c kernel/kthread.c:319
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

-> #1 (&hdev->lock){+.+.}-{3:3}:
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
sco_sock_connect+0x170/0x834 net/bluetooth/sco.c:587
__sys_connect_file net/socket.c:1899 [inline]
__sys_connect+0x268/0x290 net/socket.c:1916
__do_sys_connect net/socket.c:1926 [inline]
__se_sys_connect net/socket.c:1923 [inline]
__arm64_sys_connect+0x7c/0x94 net/socket.c:1923
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
lock_sock_nested+0xec/0x1ec net/core/sock.c:3216
lock_sock include/net/sock.h:1649 [inline]
sco_conn_del+0xf0/0x4cc net/bluetooth/sco.c:196
sco_disconn_cfm+0x8c/0xdc net/bluetooth/sco.c:1208
hci_disconn_cfm include/net/bluetooth/hci_core.h:1521 [inline]
hci_conn_hash_flush+0x104/0x208 net/bluetooth/hci_conn.c:1610
hci_dev_do_close+0x7e4/0x1020 net/bluetooth/hci_core.c:1795
hci_unregister_dev+0x228/0x48c net/bluetooth/hci_core.c:4033
vhci_release+0x74/0xc4 drivers/bluetooth/hci_vhci.c:342
__fput+0x30c/0x7f0 fs/file_table.c:280
____fput+0x20/0x30 fs/file_table.c:308
task_work_run+0x130/0x1e4 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0x688/0x2134 kernel/exit.c:872
do_group_exit+0x110/0x268 kernel/exit.c:994
__do_sys_exit_group kernel/exit.c:1005 [inline]
__se_sys_exit_group kernel/exit.c:1003 [inline]
__wake_up_parent+0x0/0x60 kernel/exit.c:1003
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(hci_cb_list_lock);
lock(&hdev->lock);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

3 locks held by syz-executor343/3976:
#0: ffff0000c80c0ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x64/0x1020 net/bluetooth/hci_core.c:1737
#1: ffff0000c80c0078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x338/0x1020 net/bluetooth/hci_core.c:1782
#2: ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
#2: ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x208 net/bluetooth/hci_conn.c:1610

stack backtrace:
CPU: 0 PID: 3976 Comm: syz-executor343 Not tainted 5.15.111-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
lock_sock_nested+0xec/0x1ec net/core/sock.c:3216
lock_sock include/net/sock.h:1649 [inline]
sco_conn_del+0xf0/0x4cc net/bluetooth/sco.c:196
sco_disconn_cfm+0x8c/0xdc net/bluetooth/sco.c:1208
hci_disconn_cfm include/net/bluetooth/hci_core.h:1521 [inline]
hci_conn_hash_flush+0x104/0x208 net/bluetooth/hci_conn.c:1610
hci_dev_do_close+0x7e4/0x1020 net/bluetooth/hci_core.c:1795
hci_unregister_dev+0x228/0x48c net/bluetooth/hci_core.c:4033
vhci_release+0x74/0xc4 drivers/bluetooth/hci_vhci.c:342
__fput+0x30c/0x7f0 fs/file_table.c:280
____fput+0x20/0x30 fs/file_table.c:308
task_work_run+0x130/0x1e4 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0x688/0x2134 kernel/exit.c:872
do_group_exit+0x110/0x268 kernel/exit.c:994
__do_sys_exit_group kernel/exit.c:1005 [inline]
__se_sys_exit_group kernel/exit.c:1003 [inline]
__wake_up_parent+0x0/0x60 kernel/exit.c:1003
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

syzbot

unread,
Jun 3, 2023, 1:22:12 AM6/3/23
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: d2869ace6eeb Linux 6.1.31
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=101bf4a5280000
kernel config: https://syzkaller.appspot.com/x/.config?x=623aacf949348d7d
dashboard link: https://syzkaller.appspot.com/bug?extid=5b0d22db545d622669cf
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b758c9280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11cd31b6280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2ed651ed0d8f/disk-d2869ace.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b8d3199c542c/vmlinux-d2869ace.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a44812549bf7/bzImage-d2869ace.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5b0d22...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.1.31-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor280/3553 is trying to acquire lock:
ffff888076942130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1721 [inline]
ffff888076942130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197

but task is already holding lock:
ffffffff8e1eb488 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1790 [inline]
ffffffff8e1eb488 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x280 net/bluetooth/hci_conn.c:2455

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
hci_connect_cfm include/net/bluetooth/hci_core.h:1775 [inline]
hci_remote_features_evt+0x671/0xaa0 net/bluetooth/hci_event.c:3753
hci_event_func net/bluetooth/hci_event.c:7476 [inline]
hci_event_packet+0x96c/0x1360 net/bluetooth/hci_event.c:7528
hci_rx_work+0x40d/0xa80 net/bluetooth/hci_core.c:4058
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x26e/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

-> #1 (&hdev->lock){+.+.}-{3:3}:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
sco_sock_connect+0x181/0x8d0 net/bluetooth/sco.c:593
__sys_connect_file net/socket.c:1976 [inline]
__sys_connect+0x2c9/0x300 net/socket.c:1993
__do_sys_connect net/socket.c:2003 [inline]
__se_sys_connect net/socket.c:2000 [inline]
__x64_sys_connect+0x76/0x80 net/socket.c:2000
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
lock_sock_nested+0x44/0x100 net/core/sock.c:3458
lock_sock include/net/sock.h:1721 [inline]
sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197
hci_disconn_cfm include/net/bluetooth/hci_core.h:1793 [inline]
hci_conn_hash_flush+0x10e/0x280 net/bluetooth/hci_conn.c:2455
hci_dev_close_sync+0xa2d/0x1000 net/bluetooth/hci_sync.c:4880
hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
hci_unregister_dev+0x1c6/0x470 net/bluetooth/hci_core.c:2702
vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:568
__fput+0x3b7/0x890 fs/file_table.c:320
task_work_run+0x246/0x300 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x6fb/0x2300 kernel/exit.c:869
do_group_exit+0x202/0x2b0 kernel/exit.c:1019
__do_sys_exit_group kernel/exit.c:1030 [inline]
__se_sys_exit_group kernel/exit.c:1028 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1028
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(hci_cb_list_lock);
lock(&hdev->lock);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

3 locks held by syz-executor280/3553:
#0: ffff888023559028 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline]
#0: ffff888023559028 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1be/0x470 net/bluetooth/hci_core.c:2702
#1: ffff888023558078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x445/0x1000 net/bluetooth/hci_sync.c:4867
#2: ffffffff8e1eb488 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1790 [inline]
#2: ffffffff8e1eb488 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x280 net/bluetooth/hci_conn.c:2455

stack backtrace:
CPU: 0 PID: 3553 Comm: syz-executor280 Not tainted 6.1.31-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
lock_sock_nested+0x44/0x100 net/core/sock.c:3458
lock_sock include/net/sock.h:1721 [inline]
sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197
hci_disconn_cfm include/net/bluetooth/hci_core.h:1793 [inline]
hci_conn_hash_flush+0x10e/0x280 net/bluetooth/hci_conn.c:2455
hci_dev_close_sync+0xa2d/0x1000 net/bluetooth/hci_sync.c:4880
hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
hci_unregister_dev+0x1c6/0x470 net/bluetooth/hci_core.c:2702
vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:568
__fput+0x3b7/0x890 fs/file_table.c:320
task_work_run+0x246/0x300 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x6fb/0x2300 kernel/exit.c:869
do_group_exit+0x202/0x2b0 kernel/exit.c:1019
__do_sys_exit_group kernel/exit.c:1030 [inline]
__se_sys_exit_group kernel/exit.c:1028 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1028
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f289dac46e9
Code: Unable to access opcode bytes at 0x7f289dac46bf.
RSP: 002b:00007fff029ae858 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f289db4e470 RCX: 00007f289dac46e9
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000007
RBP: 0000000000000007 R08: ffffffffffffffb8 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f289db4e470
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
</TASK>

syzbot

unread,
Sep 3, 2023, 6:48:45 PM9/3/23
to syzkaller...@googlegroups.com
syzbot suspects this issue could be fixed by backporting the following commit:

commit d772781964415c63759572b917e21c4f7ec08d9f
git tree: upstream
Author: Jakub Kicinski <ku...@kernel.org>
Date: Fri Jan 6 06:33:54 2023 +0000

devlink: bump the instance index directly when iterating

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16ffd2b8680000
kernel config: https://syzkaller.appspot.com/x/.config?x=623aacf949348d7d
dashboard link: https://syzkaller.appspot.com/bug?extid=5b0d22db545d622669cf
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b758c9280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11cd31b6280000


Please keep in mind that other backports might be required as well.

For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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