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

[syzbot]

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.2.3904/14857 is trying to acquire lock:
ffff88807518c078 (&hdev->lock){+.+.}-{4:4}, at: mgmt_remove_adv_monitor_complete+0xca/0x5d0 net/bluetooth/mgmt.c:5528

but task is already holding lock:
ffff88807518c078 (&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.2.3904/14857:
 #0: ffff88807518cd80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline]
 #0: ffff88807518cd80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:508
 #1: ffff88807518c078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x5d4/0x11c0 net/bluetooth/hci_sync.c:5203
 #2: ffff88807518c690 (&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: 14857 Comm: syz.2.3904 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+0xca/0x5d0 net/bluetooth/mgmt.c:5528
 _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:9561
 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: 0033:0x7f2175180849
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:00007f2175eeb058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2175345fa0 RCX: 00007f2175180849
RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000004
RBP: 00007f21751f3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2175345fa0 R15: 00007fff28348728
 </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=118e4b30580000
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=136743e8580000