============================================ WARNING: possible recursive locking detected 5.12.0-rc3-syzkaller #0 Not tainted -------------------------------------------- syz-executor.2/24589 is trying to acquire lock: ffffffff8ca63f38 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 but task is already holding lock: ffffffff8ca63f38 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 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.2/24589: #0: ffffffff8ca63f38 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 stack backtrace: CPU: 0 PID: 24589 Comm: syz-executor.2 Not tainted 5.12.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_deadlock_bug kernel/locking/lockdep.c:2829 [inline] check_deadlock kernel/locking/lockdep.c:2872 [inline] validate_chain kernel/locking/lockdep.c:3661 [inline] __lock_acquire.cold+0x14c/0x3b4 kernel/locking/lockdep.c:4900 lock_acquire kernel/locking/lockdep.c:5510 [inline] lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475 __mutex_lock_common kernel/locking/mutex.c:949 [inline] __mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096 vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 ctx_free_ctx+0x4e5/0xd30 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+0x4dc/0x620 drivers/misc/vmw_vmci/vmci_context.c:360 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:275 [inline] vmci_datagram_dispatch+0x39b/0xb50 drivers/misc/vmw_vmci/vmci_datagram.c:339 qp_notify_peer+0x182/0x260 drivers/misc/vmw_vmci/vmci_queue_pair.c:1479 vmci_qp_broker_detach+0xa09/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2186 ctx_free_ctx+0x4e5/0xd30 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+0x169/0x1d0 drivers/misc/vmw_vmci/vmci_context.c:195 vmci_host_close+0x116/0x1a0 drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x41926b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:0000000000a9fb80 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 000000000041926b RDX: 0000001b32f25054 RSI: 0000001b32f24cec RDI: 0000000000000004 RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000165e R10: 000000008afb7662 R11: 0000000000000293 R12: 000000000056c9e0 R13: 000000000056c9e0 R14: 000000000056bf60 R15: 0000000000212216