Opened 14 years ago

Closed 11 years ago

#32 closed Bug / Defect (worksforme)

BSOD hangs when is TAP- enabled. Hyperthreaded or dual core.

Reported by: Samuli Seppänen Owned by:
Priority: major Milestone:
Component: Networking Version: OpenVPN 2.1.0 / 2.1.1 (Community Ed)
Severity: Not set (select this one, unless your'e a OpenVPN developer) Keywords: bsod tap tap-windows windows


When there is any blue screen on a POSReady 2009 or XP SP3 there is a hang and no memory dump. This only happens on machines with the tap-win32 driver enabled and hyperthreading or dual cores. Turning off one of the cores or disabling hyperthreading solves this problem. The blue screen can be caused by any other driver ( We wrote a driver that causes a kebugcheck on an ioctrl to test this).
This is very repeatable using the pre-compiled driver. it was tested on many different machines. Compiling the driver as a checked build and running a kernel debugger gives no usefull results. Running PREFast on the driver gives some warnings under WDK. Some of which look worrying (to me...probably not to someone who has worked on this driver). The WDF version used was 7600.
My next step is to add in the prefast annotations and run it again. Any ideas or help would be appreciated. Or even better a fix.

Change History (8)

comment:1 Changed 14 years ago by Samuli Seppänen

This report was migrated from

comment:2 Changed 14 years ago by Samuli Seppänen

Will: Could you provide your client configuration files? Also, do you have some (other) VPN software, drivers or third-party anti-malware software running that could cause this?

comment:3 Changed 14 years ago by Samuli Seppänen

Comment from Will, report's original author:

"The hang was traced to the tap-win32 driver by doing a clean install and adding
software piece by piece till the problem occured. We have tested this on many
different machines so it is unlikely that it is a third party piece of software
or hardware. If the driver is disabled in device manager then the machine reboots
normally on a blue screen. If the processor affinity for the driver is set using
interupt-affinity filter then the machine still hangs on a BSOD. The configuration
files have not been changed. Openvpn was installed from the installer and no
changes were made from the default."

comment:4 Changed 14 years ago by WillMansell

The fault has been traced to Adapter Halt. This seems to have been used as the shutdown handler rather than the halt handler. If i`ve understood the documentation then a shutdown handler should not deallocate any resources. This should be the task of the halt handler.

comment:5 Changed 11 years ago by Samuli Seppänen

Can someone reproduce this issue on latest OpenVPN/TAP-windows versions?

comment:6 Changed 11 years ago by Samuli Seppänen

Keywords: bsod tap tap-windows added

comment:7 Changed 11 years ago by Samuli Seppänen

Keywords: windows added

comment:8 Changed 11 years ago by Samuli Seppänen

Resolution: worksforme
Status: newclosed

Nobody has reproduced this in a reasonable time. Closing, reopen if still valid.

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