linux-kernel - Re: [syzbot] [bluetooth?] possible deadlock in mgmt_set_connectable

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Message-ID: <671bada6.050a0220.2e773.0007.GAE@google.com>
Date: Fri, 25 Oct 2024 07:39:34 -0700
From: syzbot <syzbot+b1752fcfa8658bb8984a@...kaller.appspotmail.com>
To: johan.hedberg@...il.com, linux-bluetooth@...r.kernel.org, 
	linux-kernel@...r.kernel.org, luiz.dentz@...il.com, marcel@...tmann.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bluetooth?] possible deadlock in mgmt_set_connectable_complete

syzbot has found a reproducer for the following issue on:

HEAD commit:    ae90f6a6170d Merge tag 'bpf-fixes' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10bc8230580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=309bb816d40abc28
dashboard link: https://syzkaller.appspot.com/bug?extid=b1752fcfa8658bb8984a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11fab287980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-ae90f6a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c242e171fdc8/vmlinux-ae90f6a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a180678c27b3/bzImage-ae90f6a6.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2fbc68333ee1/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b1752fcfa8658bb8984a@...kaller.appspotmail.com

============================================
WARNING: possible recursive locking detected
6.12.0-rc4-syzkaller-00161-gae90f6a6170d #0 Not tainted
--------------------------------------------
syz.4.19/5588 is trying to acquire lock:
ffff888058a28078 (&hdev->lock){+.+.}-{3:3}, at: mgmt_set_connectable_complete+0xaf/0x500 net/bluetooth/mgmt.c:1690

but task is already holding lock:
ffff888058a28078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x5c8/0x11c0 net/bluetooth/hci_sync.c:5189

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.4.19/5588:
 #0: ffff888058a28d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline]
 #0: ffff888058a28d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:508
 #1: ffff888058a28078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x5c8/0x11c0 net/bluetooth/hci_sync.c:5189
 #2: ffff888058a28690 (&hdev->cmd_sync_work_lock){+.+.}-{3:3}, at: hci_cmd_sync_dequeue+0x44/0x3d0 net/bluetooth/hci_sync.c:883

stack backtrace:
CPU: 0 UID: 0 PID: 5588 Comm: syz.4.19 Not tainted 6.12.0-rc4-syzkaller-00161-gae90f6a6170d #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 mgmt_set_connectable_complete+0xaf/0x500 net/bluetooth/mgmt.c:1690
 _hci_cmd_sync_cancel_entry net/bluetooth/hci_sync.c:641 [inline]
 hci_cmd_sync_dequeue+0x22b/0x3d0 net/bluetooth/hci_sync.c:886
 cmd_complete_rsp+0x4c/0x180 net/bluetooth/mgmt.c:1461
 mgmt_pending_foreach+0xd1/0x130 net/bluetooth/mgmt_util.c:259
 __mgmt_power_off+0x183/0x430 net/bluetooth/mgmt.c:9474
 hci_dev_close_sync+0x6c4/0x11c0 net/bluetooth/hci_sync.c:5197
 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:1227
 sock_ioctl+0x626/0x8e0 net/socket.c:1346
 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: 0033:0x7f404e97e719
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:00007f404e3ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f404eb35f80 RCX: 00007f404e97e719
RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000005
RBP: 00007f404e9f132e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f404eb35f80 R15: 00007ffde86e4688
 </TASK>


---
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.