cat /proc/registry/HKEY_PERFOMANCE_DATA/@ hangs

Igor Pechtchanski
Mon Jul 19 19:47:00 GMT 2004

On Mon, 19 Jul 2004, Chris January wrote:

> > However, the fix is not as simple as inserting a "size =
> > bufalloc;" just before the RegQueryValueEx.  When I do that,
> > I get a SIGSEGV in the guts of iasperf.dll, which I have yet
> > to track down.  This happens on the second iteration, FWIW,
> > with buffer increment of 1000.  I'm going to investigate some
> > more, but I'd say that with the above bug, this key was never
> > tested, so I have no idea what's going on.  Hopefully Chris
> > (January) can use this to help him track down the problem.
> I'm back from my honeymoon (!)

Great, hope you enjoyed it...

> and I've just been catching up on this thread.

...and I'm sure you didn't enjoy this. :-)

> Are you still seeing the segfault Igor? If so I'll try to track it down
> if I have any spare time.

Yes, I'm still seeing the segfault in the latest snapshot, but only when
run under gdb or strace.  Here are some sample tests:

$ cat /proc/registry/HKEY_PERFORMANCE_DATA/\@ > e.out
cat: /proc/registry/HKEY_PERFORMANCE_DATA/@: No such file or directory
$ # no segfault
$ strace -o cat_HKPD.strace cat /proc/registry/HKEY_PERFORMANCE_DATA/\@ > e.out
2262669 [main] cat 2400 handle_exceptions: Exception: STATUS_ACCESS_VIOLATION
2264445 [main] cat 2400 open_stackdumpfile: Dumping stack trace to cat.exe.stackdump

I can also send you cat_HKPD.strace, but it's not very informative.  Let
me know if you can't reproduce this and need me to debug this locally.
FWIW, I have a working piece of Win32 code that does read this key
correctly (essentially a stripped down MS example).  Let me know if you
need it.

> As you can probably tell I never tested the HKEY_PERFORMANCE_DATA key.

Yep, so I surmised.

> Increasing the buffer size in increments is of course boilerplate code
> but I managed to cod it up regardless. Sigh.
> Chris January

      |\      _,,,---,,_
ZZZzz /,`.-'`'    -.  ;-;;,_
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"I have since come to realize that being between your mentor and his route
to the bathroom is a major career booster."  -- Patrick Naughton

Unsubscribe info:
Problem reports:

More information about the Cygwin mailing list