============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.2.1412/10628 is trying to acquire lock: ffffffff8efa1798 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x117/0xf20 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 but task is already holding lock: ffffffff8efa1798 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x117/0xf20 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 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.2.1412/10628: #0: ffffffff8efa1798 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x117/0xf20 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 stack backtrace: CPU: 1 UID: 0 PID: 10628 Comm: syz.2.1412 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x253f/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 vmci_qp_broker_detach+0x117/0xf20 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 ctx_free_ctx drivers/misc/vmw_vmci/vmci_context.c:424 [inline] kref_put include/linux/kref.h:65 [inline] vmci_ctx_put+0x64e/0xc40 drivers/misc/vmw_vmci/vmci_context.c:477 vmci_ctx_enqueue_datagram+0x3ab/0x420 drivers/misc/vmw_vmci/vmci_context.c:340 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:276 [inline] vmci_datagram_dispatch+0x450/0xc60 drivers/misc/vmw_vmci/vmci_datagram.c:340 qp_notify_peer drivers/misc/vmw_vmci/vmci_queue_pair.c:1481 [inline] vmci_qp_broker_detach+0x8dd/0xf20 drivers/misc/vmw_vmci/vmci_queue_pair.c:2188 ctx_free_ctx drivers/misc/vmw_vmci/vmci_context.c:424 [inline] kref_put include/linux/kref.h:65 [inline] vmci_ctx_put+0x64e/0xc40 drivers/misc/vmw_vmci/vmci_context.c:477 vmci_host_close+0x98/0x160 drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x44f/0xa70 fs/file_table.c:468 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcc2919aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd6dcb3008 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fcc29417da0 RCX: 00007fcc2919aeb9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fcc29417da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007fcc29417cb0 R11: 0000000000000246 R12: 0000000000069869 R13: 00007fcc29415fac R14: 0000000000069560 R15: 00007ffd6dcb3110