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charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: possible deadlock in bt_accept_dequeue ============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.3.20/6474 is trying to acquire lock: ffff888028ff2358 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] ffff888028ff2358 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x100/0x5b0 net/bluetooth/af_bluetooth.c:279 but task is already holding lock: ffff88803b4e8358 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] ffff88803b4e8358 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_release+0x5f/0x230 net/bluetooth/l2cap_sock.c:1425 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP); lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz.3.20/6474: #0: ffff88803d4c70f8 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #0: ffff88803d4c70f8 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:661 [inline] #0: ffff88803d4c70f8 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1455 #1: ffff88803b4e8358 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] #1: ffff88803b4e8358 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_release+0x5f/0x230 net/bluetooth/l2cap_sock.c:1425 stack backtrace: CPU: 0 UID: 0 PID: 6474 Comm: syz.3.20 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 lock_sock_nested+0x3e/0x130 net/core/sock.c:3720 lock_sock include/net/sock.h:1679 [inline] bt_accept_dequeue+0x100/0x5b0 net/bluetooth/af_bluetooth.c:279 l2cap_sock_cleanup_listen+0x2f/0x3e0 net/bluetooth/l2cap_sock.c:1454 l2cap_sock_release+0x67/0x230 net/bluetooth/l2cap_sock.c:1426 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe17a36f749 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:00007fff3eea6588 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fe17a5c7da0 RCX: 00007fe17a36f749 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fe17a5c7da0 R08: 0000000000000000 R09: 000000143eea687f R10: 000000000003fd20 R11: 0000000000000246 R12: 000000000002a91f R13: 00007fff3eea6680 R14: ffffffffffffffff R15: 00007fff3eea66a0 Tested on: commit: ac3fd01e Linux 6.18-rc7 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12c97612580000 kernel config: https://syzkaller.appspot.com/x/.config?x=38a0c4cddc846161 dashboard link: https://syzkaller.appspot.com/bug?extid=cdae834448ec8c3602fe compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=100f4f42580000