============================================ WARNING: possible recursive locking detected syzkaller #0 Tainted: G L -------------------------------------------- syz.3.413/7764 is trying to acquire lock: ffffffff8f7c0a10 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x14c/0x11e0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 but task is already holding lock: ffffffff8f7c0a10 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x14c/0x11e0 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.3.413/7764: #0: ffffffff8f7c0a10 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x14c/0x11e0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 stack backtrace: CPU: 1 UID: 0 PID: 7764 Comm: syz.3.413 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x12bb/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 vmci_qp_broker_detach+0x14c/0x11e0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 ctx_free_ctx+0x517/0xda0 drivers/misc/vmw_vmci/vmci_context.c:424 kref_put include/linux/kref.h:65 [inline] vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:477 [inline] vmci_ctx_enqueue_datagram+0x4be/0x5f0 drivers/misc/vmw_vmci/vmci_context.c:340 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:276 [inline] vmci_datagram_dispatch+0x3db/0xc60 drivers/misc/vmw_vmci/vmci_datagram.c:340 qp_notify_peer+0x1a6/0x230 drivers/misc/vmw_vmci/vmci_queue_pair.c:1481 vmci_qp_broker_detach+0xa20/0x11e0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2188 ctx_free_ctx+0x517/0xda0 drivers/misc/vmw_vmci/vmci_context.c:424 kref_put include/linux/kref.h:65 [inline] vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:477 [inline] vmci_ctx_destroy+0x150/0x1c0 drivers/misc/vmw_vmci/vmci_context.c:195 vmci_host_close+0x115/0x1a0 drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x3ff/0xb50 fs/file_table.c:510 task_work_run+0x150/0x240 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:67 [inline] exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline] do_syscall_64+0x706/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0cd779c819 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:00007f0cd860a028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f0cd7a16090 RCX: 00007f0cd779c819 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000005 RBP: 00007f0cd7832c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0cd7a16128 R14: 00007f0cd7a16090 R15: 00007ffcdb8642b8