Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in mgmt_remove_adv_monitor_sync

syzbot
2024-12-08T16:41:04Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in mgmt_remove_adv_monitor_complete

============================================
WARNING: possible recursive locking detected
6.13.0-rc1-syzkaller-00337-g7503345ac5f5-dirty #0 Not tainted
--------------------------------------------
syz.2.7083/22215 is trying to acquire lock:
ffff888027fbc078 (&hdev->lock){+.+.}-{4:4}, at: mgmt_remove_adv_monitor_complete+0x87/0x5f0 net/bluetooth/mgmt.c:5524

but task is already holding lock:
ffff888027fbc078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x5d4/0x11c0 net/bluetooth/hci_sync.c:5203

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&hdev->lock);
lock(&hdev->lock);

*** DEADLOCK ***

May be due to missing lock nesting notation

3 locks held by syz.2.7083/22215:
#0: ffff888027fbcd80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline]
#0: ffff888027fbcd80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:508
#1: ffff888027fbc078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x5d4/0x11c0 net/bluetooth/hci_sync.c:5203
#2: ffff888027fbc690 (&hdev->cmd_sync_work_lock){+.+.}-{4:4}, at: hci_cmd_sync_dequeue+0x44/0x3d0 net/bluetooth/hci_sync.c:887

stack backtrace:
CPU: 1 UID: 0 PID: 22215 Comm: syz.2.7083 Not tainted 6.13.0-rc1-syzkaller-00337-g7503345ac5f5-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
check_deadlock kernel/locking/lockdep.c:3089 [inline]
validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
mgmt_remove_adv_monitor_complete+0x87/0x5f0 net/bluetooth/mgmt.c:5524
_hci_cmd_sync_cancel_entry net/bluetooth/hci_sync.c:645 [inline]
hci_cmd_sync_dequeue+0x22b/0x3d0 net/bluetooth/hci_sync.c:890
cmd_complete_rsp+0x4c/0x180 net/bluetooth/mgmt.c:1469
mgmt_pending_foreach+0xd1/0x130 net/bluetooth/mgmt_util.c:259
__mgmt_power_off+0x183/0x430 net/bluetooth/mgmt.c:9560
hci_dev_close_sync+0x6d0/0x11c0 net/bluetooth/hci_sync.c:5211
hci_dev_do_close net/bluetooth/hci_core.c:483 [inline]
hci_dev_close+0x112/0x210 net/bluetooth/hci_core.c:508
sock_do_ioctl+0x158/0x460 net/socket.c:1209
sock_ioctl+0x626/0x8e0 net/socket.c:1328
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
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
RIP: 0033:0x7fa1e5980849
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa1e6784058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa1e5b45fa0 RCX: 00007fa1e5980849
RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000004
RBP: 00007fa1e59f3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa1e5b45fa0 R15: 00007ffeddc0b198
</TASK>

Tested on:

commit: 7503345a Merge tag 'block-6.13-20241207' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=115c14df980000
kernel config: https://syzkaller.appspot.com/x/.config?x=1362a5aee630ff34
dashboard link: https://syzkaller.appspot.com/bug?extid=479aff51bb361ef5aa18
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=1113c820580000