PRB: Debuggers Cannot Reliably Use Debug Register Breakpoints (137199)
The information in this article applies to:
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Professional
- Microsoft Win32 Software Development Kit (SDK) 4.0
This article was previously published under Q137199 SYMPTOMS
Debug register breakpoints are breakpoints that trigger on write or read of
a specific memory location. If you use debug register breakpoints in
application debuggers such as CodeView, Visual C++, or Windbg, other
applications in the system could fault.
CAUSE
Debug registers are not saved and restored on a per application basis in
Windows 95; they are global to the system.
A debug register running at the same address (but in another memory
context) could trigger that debug breakpoint. Because there may not be
a debugger registered to handle the breakpoint in the second application,
Windows 95 interprets this as an unhandled exception. In most cases,
this causes Windows 95 to terminate the second application, even though
it had nothing to do with the problem.
RESOLUTION
To work around this problem, use a system level debugger such as Soft-ICE
or WDEB386, or avoid using debug register breakpoints.
STATUS
This behavior is by design.
Modification Type: | Major | Last Reviewed: | 5/7/2003 |
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Keywords: | KB137199 |
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