Re: [syzbot] [bluetooth?] general protection fault in l2cap_sock_recv_cb

[syzbot <syzbot+b7f6f8c9303466e16c8a@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING: held lock freed in l2cap_sock_recv_cb

=========================
WARNING: held lock freed!
6.10.0-rc1-syzkaller-00267-gcc8ed4d0a848-dirty #0 Not tainted
-------------------------
kworker/u9:3/6458 is freeing memory ffff88802f212000-ffff88802f2127ff, with a lock still held there!
ffff88802f212258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline]
ffff88802f212258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_recv_cb+0x58/0x6f0 net/bluetooth/l2cap_sock.c:1488
3 locks held by kworker/u9:3/6458:
 #0: ffff888079178148 ((wq_completion)hci1#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
 #0: ffff888079178148 ((wq_completion)hci1#2){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
 #1: ffffc90004347d00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
 #1: ffffc90004347d00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
 #2: ffff88802f212258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline]
 #2: ffff88802f212258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_recv_cb+0x58/0x6f0 net/bluetooth/l2cap_sock.c:1488

stack backtrace:
CPU: 0 PID: 6458 Comm: kworker/u9:3 Not tainted 6.10.0-rc1-syzkaller-00267-gcc8ed4d0a848-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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
 print_freed_lock_bug kernel/locking/lockdep.c:6538 [inline]
 debug_check_no_locks_freed+0x3c5/0x4a0 kernel/locking/lockdep.c:6571
 slab_free_hook mm/slub.c:2159 [inline]
 slab_free mm/slub.c:4436 [inline]
 kfree+0xfa/0x360 mm/slub.c:4557
 sk_prot_free net/core/sock.c:2116 [inline]
 __sk_destruct+0x476/0x5f0 net/core/sock.c:2208
 sock_put include/net/sock.h:1879 [inline]
 l2cap_sock_recv_cb+0x596/0x6f0 net/bluetooth/l2cap_sock.c:1546
 l2cap_conless_channel net/bluetooth/l2cap_core.c:6780 [inline]
 l2cap_recv_frame+0x8b6d/0x10670 net/bluetooth/l2cap_core.c:6833
 hci_acldata_packet net/bluetooth/hci_core.c:3842 [inline]
 hci_rx_work+0x50f/0xca0 net/bluetooth/hci_core.c:4079
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
 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: hci1: command tx timeout


Tested on:

commit:         cc8ed4d0 Merge tag 'drm-fixes-2024-06-01' of https://g..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1082c82e980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=47d282ddffae809f
dashboard link: https://syzkaller.appspot.com/bug?extid=b7f6f8c9303466e16c8a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1706587a980000