============================================ WARNING: possible recursive locking detected 6.15.0-rc2-syzkaller-00404-g8560697b23dc #0 Not tainted -------------------------------------------- syz.0.1163/9993 is trying to acquire lock: ffffffff8f327798 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x14c/0x1380 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 but task is already holding lock: ffffffff8f327798 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x14c/0x1380 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.0.1163/9993: #0: ffffffff8f327798 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x14c/0x1380 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 stack backtrace: CPU: 2 UID: 0 PID: 9993 Comm: syz.0.1163 Not tainted 6.15.0-rc2-syzkaller-00404-g8560697b23dc #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_deadlock_bug+0x1e9/0x240 kernel/locking/lockdep.c:3042 check_deadlock kernel/locking/lockdep.c:3094 [inline] validate_chain kernel/locking/lockdep.c:3896 [inline] __lock_acquire+0xff7/0x1ba0 kernel/locking/lockdep.c:5235 lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 vmci_qp_broker_detach+0x14c/0x1380 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095 ctx_free_ctx+0x4f5/0xd70 drivers/misc/vmw_vmci/vmci_context.c:444 kref_put include/linux/kref.h:65 [inline] vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:497 [inline] vmci_ctx_enqueue_datagram+0x4c5/0x650 drivers/misc/vmw_vmci/vmci_context.c:360 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:276 [inline] vmci_datagram_dispatch+0x42e/0xd30 drivers/misc/vmw_vmci/vmci_datagram.c:340 qp_notify_peer+0x19d/0x260 drivers/misc/vmw_vmci/vmci_queue_pair.c:1481 vmci_qp_broker_detach+0x604/0x1380 drivers/misc/vmw_vmci/vmci_queue_pair.c:2188 ctx_free_ctx+0x4f5/0xd70 drivers/misc/vmw_vmci/vmci_context.c:444 kref_put include/linux/kref.h:65 [inline] vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:497 [inline] vmci_ctx_destroy+0x15b/0x1d0 drivers/misc/vmw_vmci/vmci_context.c:195 vmci_host_close+0x115/0x1a0 drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f43f538e169 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:00007f43f62b8038 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f43f55b5fa0 RCX: 00007f43f538e169 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000000 RBP: 00007f43f5410a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f43f55b5fa0 R15: 00007ffdbb20bda8 </TASK>