============================================
WARNING: possible recursive locking detected
--------------------------------------------
syz.2.97/6276 is trying to acquire lock:
ffffffff8e967ec8 (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:
ffffffff8e967ec8 (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.2.97/6276:
#0: ffffffff8e967ec8 (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: 0 UID: 0 PID: 6276 Comm: syz.2.97 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3043
check_deadlock kernel/locking/lockdep.c:3095 [inline]
validate_chain kernel/locking/lockdep.c:3897 [inline]
__lock_acquire+0x255f/0x2d10 kernel/locking/lockdep.c:5239
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
__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:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fca6ca0cdd9
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:00007fca6ac1c028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fca6cc86180 RCX: 00007fca6ca0cdd9
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000005
RBP: 00007fca6caa2d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fca6cc86218 R14: 00007fca6cc86180 R15: 00007ffc93ec68b8
Oops: general protection fault, probably for non-canonical address 0xdffffc000000015b: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000ad8-0x0000000000000adf]
CPU: 0 UID: 0 PID: 6276 Comm: syz.2.97 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
RIP: 0010:do_raw_spin_lock+0x73/0x2f0 kernel/locking/spinlock_debug.c:115
Code: c7 44 24 30 f0 0d a1 81 4c 8d 64 24 20 49 c1 ec 03 48 b8 f1 f1 f1 f1 f8 f3 f3 f3 49 89 04 14 4c 8d 77 04 4c 89 f0 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 f3 01 00 00 41 8b 06 3d ad 4e ad de 0f 85
RSP: 0018:ffffc900063af300 EFLAGS: 00010003
RAX: 000000000000015b RBX: 0000000000000ad8 RCX: 0000000080000003
RDX: dffffc0000000000 RSI: ffffffff8ba86040 RDI: 0000000000000ad8
RBP: ffffc900063af3c0 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f1509f R12: 1ffff92000c75e64
R13: ffffc900063af4c0 R14: 0000000000000adc R15: 0000000000000ad8
FS: 00007fca6ac1c6c0(0000) GS:ffff888125f2a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000002b030 CR3: 0000000037d48000 CR4: 00000000003526f0
Call Trace:
class_raw_spinlock_constructor include/linux/spinlock.h:535 [inline]
remove_waiter+0x138/0xb10 kernel/locking/rtmutex.c:1561
__rt_mutex_slowlock kernel/locking/rtmutex.c:1751 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1779 [inline]
rt_mutex_slowlock+0x72d/0x780 kernel/locking/rtmutex.c:1819
__rt_mutex_lock kernel/locking/rtmutex.c:1834 [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:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fca6ca0cdd9
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:00007fca6ac1c028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fca6cc86180 RCX: 00007fca6ca0cdd9
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000005
RBP: 00007fca6caa2d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fca6cc86218 R14: 00007fca6cc86180 R15: 00007ffc93ec68b8
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
RIP: 0010:do_raw_spin_lock+0x73/0x2f0 kernel/locking/spinlock_debug.c:115
Code: c7 44 24 30 f0 0d a1 81 4c 8d 64 24 20 49 c1 ec 03 48 b8 f1 f1 f1 f1 f8 f3 f3 f3 49 89 04 14 4c 8d 77 04 4c 89 f0 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 f3 01 00 00 41 8b 06 3d ad 4e ad de 0f 85
RSP: 0018:ffffc900063af300 EFLAGS: 00010003
RAX: 000000000000015b RBX: 0000000000000ad8 RCX: 0000000080000003
RDX: dffffc0000000000 RSI: ffffffff8ba86040 RDI: 0000000000000ad8
RBP: ffffc900063af3c0 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f1509f R12: 1ffff92000c75e64
R13: ffffc900063af4c0 R14: 0000000000000adc R15: 0000000000000ad8
FS: 00007fca6ac1c6c0(0000) GS:ffff888125f2a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000002b030 CR3: 0000000037d48000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: c7 44 24 30 f0 0d a1 movl $0x81a10df0,0x30(%rsp)
7: 81
8: 4c 8d 64 24 20 lea 0x20(%rsp),%r12
d: 49 c1 ec 03 shr $0x3,%r12
11: 48 b8 f1 f1 f1 f1 f8 movabs $0xf3f3f3f8f1f1f1f1,%rax
18: f3 f3 f3
1b: 49 89 04 14 mov %rax,(%r12,%rdx,1)
1f: 4c 8d 77 04 lea 0x4(%rdi),%r14
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 f3 01 00 00 jne 0x229
36: 41 8b 06 mov (%r14),%eax
39: 3d ad 4e ad de cmp $0xdead4ead,%eax
3e: 0f .byte 0xf
3f: 85 .byte 0x85