============================================ WARNING: possible recursive locking detected 6.0.0-rc2-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/4080 is trying to acquire lock: ffff8880215f1130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline] ffff8880215f1130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x58/0x320 net/bluetooth/rfcomm/sock.c:73 but task is already holding lock: ffff8880215f1130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline] ffff8880215f1130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x44/0x1c0 net/bluetooth/rfcomm/sock.c:902 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by syz-executor.0/4080: #0: ffff8880730d5610 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] #0: ffff8880730d5610 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: __sock_release+0x76/0x270 net/socket.c:649 #1: ffff8880215f1130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline] #1: ffff8880215f1130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x44/0x1c0 net/bluetooth/rfcomm/sock.c:902 #2: ffffffff8cab2a08 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x25/0x200 net/bluetooth/rfcomm/core.c:507 #3: ffff88807210c128 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0xff/0x770 net/bluetooth/rfcomm/core.c:487 stack backtrace: CPU: 0 PID: 4080 Comm: syz-executor.0 Not tainted 6.0.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain kernel/locking/lockdep.c:3816 [inline] __lock_acquire.cold+0x116/0x397 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 lock_sock_nested+0x2b/0xd0 net/core/sock.c:3391 lock_sock include/net/sock.h:1712 [inline] rfcomm_sk_state_change+0x58/0x320 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x153/0x770 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0x1a4/0x200 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x10d/0x200 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xa4/0x1c0 net/bluetooth/rfcomm/sock.c:905 rfcomm_sock_release+0x4f/0x120 net/bluetooth/rfcomm/sock.c:925 __sock_release+0xbb/0x270 net/socket.c:650 sock_close+0xf/0x20 net/socket.c:1365 __fput+0x1f5/0x8c0 fs/file_table.c:320 task_work_run+0xc0/0x160 kernel/task_work.c:177 get_signal+0x19a/0x1e40 kernel/signal.c:2634 arch_do_signal_or_restart+0x88/0x1b00 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop kernel/entry/common.c:166 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294 do_syscall_64+0x42/0x80 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f30ae289049 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f30af3ad168 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 00007f30ae39bf60 RCX: 00007f30ae289049 RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004 RBP: 00007f30ae2e308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffedf08a26f R14: 00007f30af3ad300 R15: 0000000000022000