============================================ WARNING: possible recursive locking detected syzkaller #0 Tainted: G L -------------------------------------------- syz.2.5736/26462 is trying to acquire lock: ffffffff8ed44c18 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x113/0xf10 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 but task is already holding lock: ffffffff8ed44c18 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x113/0xf10 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.2.5736/26462: #0: ffffffff8ed44c18 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x113/0xf10 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 stack backtrace: CPU: 0 UID: 0 PID: 26462 Comm: syz.2.5736 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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+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+0x2540/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 vmci_qp_broker_detach+0x113/0xf10 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+0x603/0xbf0 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+0x43f/0xc10 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+0x8c8/0xf10 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+0x603/0xbf0 drivers/misc/vmw_vmci/vmci_context.c:477 vmci_host_close+0x98/0x160 drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d4/0x260 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+0xff/0x4f0 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+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff20058f749 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:00007ff201467038 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007ff2007e6090 RCX: 00007ff20058f749 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000004 RBP: 00007ff200613f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff2007e6128 R14: 00007ff2007e6090 R15: 00007ffe662a4a78