[syzbot] [bluetooth?] possible deadlock in sco_connect_cfm

From: syzbot
Date: Mon Jul 08 2024 - 14:22:38 EST

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Hello,

syzbot found the following issue on:

HEAD commit: d270dd21bee0 Merge tag 'pci-v6.10-fixes-2' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1009bb81980000
kernel config: https://syzkaller.appspot.com/x/.config?x=1ace69f521989b1f
dashboard link: https://syzkaller.appspot.com/bug?extid=0068c4f72ae17f8a1605
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/119d89656b6c/disk-d270dd21.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6a5dce1ccbf0/vmlinux-d270dd21.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e7b7e333da4e/bzImage-d270dd21.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0068c4f72ae17f8a1605@xxxxxxxxxxxxxxxxxxxxxxxxx

Bluetooth: hci6: unexpected cc 0x0c03 length: 249 > 1
Bluetooth: hci6: unexpected cc 0x1003 length: 249 > 9
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc6-syzkaller-00210-gd270dd21bee0 #0 Not tainted
------------------------------------------------------
kworker/u9:2/5087 is trying to acquire lock:
ffff88807ad7a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline]
ffff88807ad7a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_ready net/bluetooth/sco.c:1290 [inline]
ffff88807ad7a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x461/0xb40 net/bluetooth/sco.c:1362

but task is already holding lock:
ffff8880274ab820 (&conn->lock#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff8880274ab820 (&conn->lock#2){+.+.}-{2:2}, at: sco_conn_ready net/bluetooth/sco.c:1277 [inline]
ffff8880274ab820 (&conn->lock#2){+.+.}-{2:2}, at: sco_connect_cfm+0x28a/0xb40 net/bluetooth/sco.c:1362

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&conn->lock#2){+.+.}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
sco_chan_add net/bluetooth/sco.c:234 [inline]
sco_connect net/bluetooth/sco.c:287 [inline]
sco_sock_connect+0x347/0x990 net/bluetooth/sco.c:596
io_connect+0xa4/0x4f0 io_uring/net.c:1687
io_issue_sqe+0x3cf/0x14f0 io_uring/io_uring.c:1751
io_queue_sqe io_uring/io_uring.c:1965 [inline]
io_submit_sqe io_uring/io_uring.c:2221 [inline]
io_submit_sqes+0xaff/0x1bf0 io_uring/io_uring.c:2336
__do_sys_io_uring_enter io_uring/io_uring.c:3245 [inline]
__se_sys_io_uring_enter+0x2d4/0x2670 io_uring/io_uring.c:3182
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
lock_sock_nested+0x48/0x100 net/core/sock.c:3534
lock_sock include/net/sock.h:1602 [inline]
sco_conn_ready net/bluetooth/sco.c:1290 [inline]
sco_connect_cfm+0x461/0xb40 net/bluetooth/sco.c:1362
hci_connect_cfm include/net/bluetooth/hci_core.h:1970 [inline]
hci_sync_conn_complete_evt+0x5ab/0xaa0 net/bluetooth/hci_event.c:5009
hci_event_func net/bluetooth/hci_event.c:7444 [inline]
hci_event_packet+0xac0/0x1540 net/bluetooth/hci_event.c:7496
hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4042
process_one_work kernel/workqueue.c:3248 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
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(&conn->lock#2);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);
lock(&conn->lock#2);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

5 locks held by kworker/u9:2/5087:
#0: ffff8880764d1948 ((wq_completion)hci1#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3223 [inline]
#0: ffff8880764d1948 ((wq_completion)hci1#2){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3329
#1: ffffc9000377fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3224 [inline]
#1: ffffc9000377fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3329
#2: ffff88802d30c078 (&hdev->lock){+.+.}-{3:3}, at: hci_sync_conn_complete_evt+0xb1/0xaa0 net/bluetooth/hci_event.c:4926
#3: ffffffff8f73f008 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:1967 [inline]
#3: ffffffff8f73f008 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_sync_conn_complete_evt+0x532/0xaa0 net/bluetooth/hci_event.c:5009
#4: ffff8880274ab820 (&conn->lock#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#4: ffff8880274ab820 (&conn->lock#2){+.+.}-{2:2}, at: sco_conn_ready net/bluetooth/sco.c:1277 [inline]
#4: ffff8880274ab820 (&conn->lock#2){+.+.}-{2:2}, at: sco_connect_cfm+0x28a/0xb40 net/bluetooth/sco.c:1362

stack backtrace:
CPU: 1 PID: 5087 Comm: kworker/u9:2 Not tainted 6.10.0-rc6-syzkaller-00210-gd270dd21bee0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: hci1 hci_rx_work
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+0x18e0/0x5900 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
lock_sock_nested+0x48/0x100 net/core/sock.c:3534
lock_sock include/net/sock.h:1602 [inline]
sco_conn_ready net/bluetooth/sco.c:1290 [inline]
sco_connect_cfm+0x461/0xb40 net/bluetooth/sco.c:1362
hci_connect_cfm include/net/bluetooth/hci_core.h:1970 [inline]
hci_sync_conn_complete_evt+0x5ab/0xaa0 net/bluetooth/hci_event.c:5009
hci_event_func net/bluetooth/hci_event.c:7444 [inline]
hci_event_packet+0xac0/0x1540 net/bluetooth/hci_event.c:7496
hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4042
process_one_work kernel/workqueue.c:3248 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
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>
BUG: sleeping function called from invalid context at net/core/sock.c:3536
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5087, name: kworker/u9:2
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 PID: 5087 Comm: kworker/u9:2 Not tainted 6.10.0-rc6-syzkaller-00210-gd270dd21bee0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: hci1 hci_rx_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
__might_resched+0x5d4/0x780 kernel/sched/core.c:10196
lock_sock_nested+0x5d/0x100 net/core/sock.c:3536
lock_sock include/net/sock.h:1602 [inline]
sco_conn_ready net/bluetooth/sco.c:1290 [inline]
sco_connect_cfm+0x461/0xb40 net/bluetooth/sco.c:1362
hci_connect_cfm include/net/bluetooth/hci_core.h:1970 [inline]
hci_sync_conn_complete_evt+0x5ab/0xaa0 net/bluetooth/hci_event.c:5009
hci_event_func net/bluetooth/hci_event.c:7444 [inline]
hci_event_packet+0xac0/0x1540 net/bluetooth/hci_event.c:7496
hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4042
process_one_work kernel/workqueue.c:3248 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
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>
Bluetooth: hci6: unexpected cc 0x0c23 length: 249 > 4

---
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Next message: Markus Elfring: "Re: [PATCH] phy: exynos5-usbdrd: fix error code in probe()"
Previous message: Mirsad Todorovac: "Re: [PROBLEM] ./arch/x86/include/asm/pgtable_32.h:59:5: error: "PTRS_PER_PMD" is not defined, evaluates to 0 [-Werror=undef]"
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