Bug Check 0x20: KERNEL_APC_PENDING_DURING_EXIT
The KERNEL_APC_PENDING_DURING_EXIT bug check has a value of 0x00000020. This indicates that an asynchronous procedure call (APC) was still pending when a thread exited.
Important Info If You Have Received a STOP Code
If you received a blue screen error, or stop code, the computer has shut down abruptly to protect itself from data loss. A hardware device, its driver, or related software might have caused this error. If your copy of Windows came with your computer, call the manufacturer of your computer. If you purchased Windows separately from your computer, Microsoft provides support. To find contact info for Microsoft or your computer manufacturer, Contact Support.
If you have experience with computers and want to try to recover from this error, follow the steps provided in the Microsoft article Resolving STOP (Blue Screen) Errors in Windows.
These actions might prevent an error like this from happening again:
- Download and install updates and device drivers for your computer from Windows Update.
- Scan your computer for computer viruses.
- Check your hard disk for errors.
KERNEL_APC_PENDING_DURING_EXIT Parameters
The following parameters are displayed on the blue screen.
| Parameter | Description |
|---|---|
|
1 |
The address of the APC found pending during exit |
|
2 |
The thread's APC disable count |
|
3 |
The current IRQL |
|
4 |
Reserved |
Cause
The key data item is the APC disable count (Parameter 2) for the thread. If the count is nonzero, it will indicate the source of the problem.
The APC disable count is decremented each time a driver calls KeEnterCriticalRegion, FsRtlEnterFileSystem, or acquires a mutex.
The APC disable count is incremented each time a driver calls KeLeaveCriticalRegion, KeReleaseMutex, or FsRtlExitFileSystem.
Because these calls should always be in pairs, the APC disable count should be zero when a thread exits. A negative value indicates that a driver has disabled APC calls without re-enabling them. A positive value indicates that the reverse is true.
If you ever see this error, be very suspicious of all drivers installed on the machine -- especially unusual or non-standard drivers.
This current IRQL (Parameter 3) should be zero. If it is not, the driver's cancellation routine may have caused this bug check by returning at an elevated IRQL. In this case, carefully note what was running (and what was closing) at the time of the crash, and note all of the installed drivers at the time of the crash. The cause in this case is usually a severe bug in a driver.
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Build date: 4/9/2013
