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

[syzbot]

Hello,

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

============================================
WARNING: possible recursive locking detected
6.11.0-syzkaller-11519-gc30a3f54e661-dirty #0 Not tainted
--------------------------------------------
syz.0.15/6089 is trying to acquire lock:
ffff88802cd3cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x66e/0x11b0 net/bluetooth/hci_sync.c:5191

but task is already holding lock:
ffff88802cd3cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline]
ffff88802cd3cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:508

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

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

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz.0.15/6089:
 #0: ffff88802cd3cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline]
 #0: ffff88802cd3cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:508
 #1: ffff88802cd3c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x572/0x11b0 net/bluetooth/hci_sync.c:5183

stack backtrace:
CPU: 1 UID: 0 PID: 6089 Comm: syz.0.15 Not tainted 6.11.0-syzkaller-11519-gc30a3f54e661-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:3034
 check_deadlock kernel/locking/lockdep.c:3086 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3888
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 hci_dev_close_sync+0x66e/0x11b0 net/bluetooth/hci_sync.c:5191
 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:1228
 sock_ioctl+0x626/0x8e0 net/socket.c:1347
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 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: 0033:0x7fe0fa37cef9
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:00007fe0fb0e2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe0fa536058 RCX: 00007fe0fa37cef9
RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000008
RBP: 00007fe0fa3ef046 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe0fa536058 R15: 00007fff1e0b61e8
 </TASK>


Tested on:

commit:         c30a3f54 net: mana: Add get_link and get_link_ksetting..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13ea7580580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b2d4fdf18a83ec0b
dashboard link: https://syzkaller.appspot.com/bug?extid=03d6270b6425df1605bf
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16806307980000