Context (ID=0x1) not attached to queue pair (handle=0x2:0x0)
Context (ID=0x10) not attached to queue pair (handle=0x2:0x0)
============================================
WARNING: possible recursive locking detected
4.19.163-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.1/10709 is trying to acquire lock:
00000000878db8f2 (qp_broker_list.mutex){+.+.}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2096

but task is already holding lock:
00000000878db8f2 (qp_broker_list.mutex){+.+.}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2096

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

       CPU0
       ----
  lock(qp_broker_list.mutex);
  lock(qp_broker_list.mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by syz-executor.1/10709:
 #0: 00000000878db8f2 (qp_broker_list.mutex){+.+.}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2096

stack backtrace:
CPU: 1 PID: 10709 Comm: syz-executor.1 Not tainted 4.19.163-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
 print_deadlock_bug kernel/locking/lockdep.c:1763 [inline]
 check_deadlock kernel/locking/lockdep.c:1807 [inline]
 validate_chain kernel/locking/lockdep.c:2403 [inline]
 __lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3415
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907
 __mutex_lock_common kernel/locking/mutex.c:925 [inline]
 __mutex_lock+0xd7/0x1260 kernel/locking/mutex.c:1072
 vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2096
 ctx_free_ctx drivers/misc/vmw_vmci/vmci_context.c:452 [inline]
 kref_put include/linux/kref.h:70 [inline]
 vmci_ctx_put+0x55a/0xd60 drivers/misc/vmw_vmci/vmci_context.c:505
 vmci_ctx_enqueue_datagram+0x3f7/0x500 drivers/misc/vmw_vmci/vmci_context.c:368
 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:283 [inline]
 vmci_datagram_dispatch+0x39b/0xb40 drivers/misc/vmw_vmci/vmci_datagram.c:347
 qp_notify_peer+0x182/0x260 drivers/misc/vmw_vmci/vmci_queue_pair.c:1485
 vmci_qp_broker_detach+0xa09/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2189
 ctx_free_ctx drivers/misc/vmw_vmci/vmci_context.c:452 [inline]
 kref_put include/linux/kref.h:70 [inline]
 vmci_ctx_put+0x55a/0xd60 drivers/misc/vmw_vmci/vmci_context.c:505
 vmci_host_close+0x116/0x1a0 drivers/misc/vmw_vmci/vmci_host.c:147
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x417bf1
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fff3f955350 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000417bf1
RDX: 0000001b2cb20000 RSI: ffffffff8820008d RDI: 0000000000000003
RBP: 0000000000000001 R08: ffffffff812cc51f R09: 000000006494ec27
R10: 00007fff3f955430 R11: 0000000000000293 R12: ffffffffffffffff
R13: 00000000000bf5f1 R14: 00000000000003e8 R15: 000000000119bf8c