============================================ WARNING: possible recursive locking detected syzkaller #0 Tainted: G L -------------------------------------------- syz.7.6222/23735 is trying to acquire lock: ffffffff90e7c0b0 (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: ffffffff90e7c0b0 (qp_broker_list.mutex){+.+.}-{4:4}, at: qp_broker_alloc+0x2a2/0x1bc0 drivers/misc/vmw_vmci/vmci_queue_pair.c:1731 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 locks held by syz.7.6222/23735: 1, last CPU#0: #0: ffffffff90e7c0b0 (qp_broker_list.mutex){+.+.}-{4:4}, at: qp_broker_alloc+0x2a2/0x1bc0 drivers/misc/vmw_vmci/vmci_queue_pair.c:1731 stack backtrace: CPU: 0 UID: 0 PID: 23735 Comm: syz.7.6222 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 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:3085 check_deadlock kernel/locking/lockdep.c:3137 [inline] validate_chain kernel/locking/lockdep.c:3939 [inline] __lock_acquire+0x13f4/0x1f40 kernel/locking/lockdep.c:5288 lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 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 qp_broker_attach drivers/misc/vmw_vmci/vmci_queue_pair.c:1664 [inline] qp_broker_alloc+0x8c9/0x1bc0 drivers/misc/vmw_vmci/vmci_queue_pair.c:1752 vmci_qp_broker_alloc+0x93/0xc0 drivers/misc/vmw_vmci/vmci_queue_pair.c:1942 vmci_host_do_alloc_queuepair.constprop.0+0x30b/0x3f0 drivers/misc/vmw_vmci/vmci_host.c:495 vmci_host_unlocked_ioctl+0x697/0x2070 drivers/misc/vmw_vmci/vmci_host.c:934 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa94f59e1d9 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:00007fa95037e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa94f825fa0 RCX: 00007fa94f59e1d9 RDX: 0000200000000300 RSI: 00000000000007a8 RDI: 0000000000000005 RBP: 00007fa94f635888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa94f826038 R14: 00007fa94f825fa0 R15: 00007ffec5eacdd8