Bug Check 0x1AB: UNWIND_ON_INVALID_STACK
The UNWIND_ON_INVALID_STACK bug check has a value of 0x000001AB. It indicates that an attempt was made to access memory outside of the valid kernel stack range. In particular, this BugCheck indicates that stack unwinding crossed over into an invalid kernel stack. This might indicate that the kernel stack pointer has become corrupted during exception dispatch or unwind (e.g. due to stack corruption of a frame pointer), or that a driver is executing off of a stack that is not a legal kernel stack.
At the time the invalid access occurred, the exception record was not available.
Important
This article is for programmers. If you're a customer who has received a blue screen error code while using your computer, see Troubleshoot blue screen errors.
UNWIND_ON_INVALID_STACK Parameters
| Parameter | Description |
|---|---|
1 |
A pointer to the current stack. |
2 |
The Type of stack limit such as NormalStackLimits (3). Because the
stack is invalid, this represents the kernel's best estimation as to
the type of kernel stack that should be active given the state of the
machine. Stack limit type:
|
3 |
A pointer to the context record representing the context that was being unwound (or dispatched for an exception) when the invalid stack was encountered. |
4 |
ExceptionRecord - Reserved and always 0 for UNWIND_ON_INVALID_STACK. |
Cause
An attempt to access an invalid stack occurred. As kernel stack is limited in size, the developer needs to be careful with tracking it limits, for example when using it to copy blocks of video memory. For information about the Windows Kernel stack, see Using the Kernel Stack.
Resolution
Using a full kernel dump or an attached debugger, the following commands may be useful to gather information and track down the code that is incorrectly accessing memory.
First use the !analyze command to gather information, in particular the bug check parameters. Also examine the faulting source line and module name, if available.
Arguments:
Arg1: 89344350fffff607
Arg2: 0000000000000003
Arg3: fffff607893436c4
Arg4: fffff60789343ea8
Use the provided .trap command link in the !analyze output to set the context to the trap frame.
TRAP_FRAME: fffff60789343f50 -- (.trap 0xfffff60789343f50)
NOTE: The trap frame does not contain all registers.
Some register values may be zeroed or incorrect.
rax=fffff607893441e8 rbx=0000000000000000 rcx=0000000010000004
rdx=0000000000000002 rsi=0000000000000000 rdi=0000000000000000
rip=fffff8026dc296cf rsp=fffff607893440e8 rbp=fffff60789344350
r8=fffff8028e7a08b2 r9=0000000000000008 r10=fffff8029e9c3980
r11=fffff607893440f8 r12=0000000000000000 r13=0000000000000000
r14=0000000000000000 r15=0000000000000000
Use the !thread command to gather information on what is running. In this example it looks like a video scheduler worker thread is running.
2: kd> !thread
THREAD ffff8f8e9af25080 Cid 0004.0378 Teb: 0000000000000000 Win32Thread: 0000000000000000 RUNNING on processor 2
Not impersonating
DeviceMap ffffd601dbe63e30
Owning Process ffff8f8e99ab4040 Image: System
Attached Process N/A Image: N/A
Wait Start TickCount 14361 Ticks: 0
Context Switch Count 64607 IdealProcessor: 1
UserTime 00:00:00.000
KernelTime 00:00:06.046
Win32 Start Address dxgmms2!VidSchiWorkerThread (0xfffff8027a70d100)
Stack Init fffff60789344c70 Current fffff607893445c0
Base fffff60789345000 Limit fffff6078933f000 Call 0000000000000000
Priority 16 BasePriority 16 PriorityDecrement 0 IoPriority 2 PagePriority 5
...
Then use kb (Display Stack Backtrace) with the f option to display the stack and the memory usage to see if there is a large memory user.
2: kd> kf
...
02 198 fffff607`89344460 fffff802`8e6b41d5 amdkmdag+0x2308b2
03 120 fffff607`89344580 fffff802`8e59eb35 amdkmdag+0x1441d5
04 30 fffff607`893445b0 fffff802`8e62b5e8 amdkmdag+0x2eb35
05 c0 fffff607`89344670 fffff802`8e623f6c amdkmdag+0xbb5e8
...
If a specific part of the code looks suspicious, use the u, ub, uu (Unassemble) command to examine the associated assemble language code.
2: kd> u fffff607`893442c8 l10
fffff607`893442c8 d04234 rol byte ptr [rdx+34h],1
fffff607`893442cb 8907 mov dword ptr [rdi],eax
fffff607`893442cd f6ff idiv bh
fffff607`893442cf ff01 inc dword ptr [rcx]
fffff607`893442d1 17 ???
fffff607`893442d2 c4 ???
fffff607`893442d3 9f lahf
fffff607`893442d4 8e8fffff0060 mov cs,word ptr [rdi+6000FFFFh]
fffff607`893442da 5a pop rdx
fffff607`893442db 9f lahf
fffff607`893442dc 8e8fffff0000 mov cs,word ptr [rdi+0FFFFh]
fffff607`893442e2 0000 add byte ptr [rax],al
fffff607`893442e4 0000 add byte ptr [rax],al
fffff607`893442e6 0000 add byte ptr [rax],al
fffff607`893442e8 7527 jne fffff607`89344311
fffff607`893442ea 6e outs dx,byte ptr [rsi]
Use the .cxr (Display Context Record) command to display the context record, using the parameter 3 value provided by !analyze.
.cxr fffff607893436c4
Use the !vm command to examine memory usage, for example of to see how much of the Kernel Stacks memory is in use.
0: kd> !vm
Physical Memory: 1541186 ( 6164744 Kb)
Available Pages: 470550 ( 1882200 Kb)
ResAvail Pages: 1279680 ( 5118720 Kb)
...
Kernel Stacks: 13686 ( 54744 Kb)
Use the !stacks command, with the 2 parameter to view information about stacks. This command may take some time to run. Examine the output for repeated patterns of blocked execution that may point towards and area for further investigation.