============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.3.140/6375 is trying to acquire lock:
ffffffff8e94b268 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x117/0xf10 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095
but task is already holding lock:
ffffffff8e94b268 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x117/0xf10 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.3.140/6375:
#0: ffffffff8e94b268 (qp_broker_list.mutex){+.+.}-{4:4}, at: vmci_qp_broker_detach+0x117/0xf10 drivers/misc/vmw_vmci/vmci_queue_pair.c:2095
stack backtrace:
CPU: 1 UID: 0 PID: 6375 Comm: syz.3.140 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 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+0x253f/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:553
vmci_qp_broker_detach+0x117/0xf10 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+0x64e/0xc40 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+0x450/0xc60 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+0x8d4/0xf10 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+0x64e/0xc40 drivers/misc/vmw_vmci/vmci_context.c:477
vmci_host_close+0x9b/0x160 drivers/misc/vmw_vmci/vmci_host.c:143
__fput+0x461/0xa70 fs/file_table.c:510
task_work_run+0x1d9/0x270 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+0xed/0x480 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+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3decdac819
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:00007f3deafbc028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f3ded026180 RCX: 00007f3decdac819
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000005
RBP: 00007f3dece42c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3ded026218 R14: 00007f3ded026180 R15: 00007ffd90d87e58
------------[ cut here ]------------
rtmutex deadlock detected
WARNING: kernel/locking/rtmutex.c:1687 at rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1687, CPU#1: syz.3.140/6375
Modules linked in:
CPU: 1 UID: 0 PID: 6375 Comm: syz.3.140 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1687
Code: 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 41 54 53 83 ff dd 0f 85 81 00 00 00 48 89 f7 e8 d6 3a 01 00 48 8d 3d 5f d8 63 04 <67> 48 0f b9 3a 4c 8d 3d 00 00 00 00 65 48 8b 1d 13 0e 46 07 4c 8d
RSP: 0018:ffffc90008197430 EFLAGS: 00010286
RAX: 0000000080000000 RBX: ffffc900081974c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8ba70360 RDI: ffffffff8f8e7a40
RBP: ffffc900081975e0 R08: ffffffff8f8b46b7 R09: 1ffffffff1f168d6
R10: dffffc0000000000 R11: fffffbfff1f168d7 R12: 1ffff92001032e94
R13: ffffffff8b2a9c2d R14: ffffffff8e94b210 R15: dffffc0000000000
FS: 00007f3deafbc6c0(0000) GS:ffff888126215000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f63ddfb56b8 CR3: 000000003d49c000 CR4: 00000000003526f0
Call Trace:
__rt_mutex_slowlock kernel/locking/rtmutex.c:1749 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1776 [inline]
rt_mutex_slowlock+0x73a/0x780 kernel/locking/rtmutex.c:1816
__rt_mutex_lock kernel/locking/rtmutex.c:1831 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553
vmci_qp_broker_detach+0x117/0xf10 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+0x64e/0xc40 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+0x450/0xc60 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+0x8d4/0xf10 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+0x64e/0xc40 drivers/misc/vmw_vmci/vmci_context.c:477
vmci_host_close+0x9b/0x160 drivers/misc/vmw_vmci/vmci_host.c:143
__fput+0x461/0xa70 fs/file_table.c:510
task_work_run+0x1d9/0x270 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+0xed/0x480 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+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3decdac819
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:00007f3deafbc028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f3ded026180 RCX: 00007f3decdac819
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000005
RBP: 00007f3dece42c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3ded026218 R14: 00007f3ded026180 R15: 00007ffd90d87e58
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 90 nop
3: 90 nop
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 41 57 push %r15
b: 41 56 push %r14
d: 41 55 push %r13
f: 41 54 push %r12
11: 53 push %rbx
12: 83 ff dd cmp $0xffffffdd,%edi
15: 0f 85 81 00 00 00 jne 0x9c
1b: 48 89 f7 mov %rsi,%rdi
1e: e8 d6 3a 01 00 call 0x13af9
23: 48 8d 3d 5f d8 63 04 lea 0x463d85f(%rip),%rdi # 0x463d889
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 4c 8d 3d 00 00 00 00 lea 0x0(%rip),%r15 # 0x36
36: 65 48 8b 1d 13 0e 46 mov %gs:0x7460e13(%rip),%rbx # 0x7460e51
3d: 07
3e: 4c rex.WR
3f: 8d .byte 0x8d