Breakpoint (WinDbg)

NTDEV
1

I have set a break-point using “bu” in WinDbg.
But the break-point doesn’t seems to work always.
The OS is not breaking into the debugger every time (it breaks
sometimes, whereas it is expected to break always). Has anybody
encountered such an irregular behaviour of WinDbg.

2

Tell us more about what is happening?

If you don’t get symbols loaded, then breakpoints will not get set. That
happens to me sometimes when I’ve forgottent to click OK to the message box
saying “Do you want to save settngs?” when rebooting. In that situation, the
debugger does not receive the message that a module has been loaded, and it
doesn’t load the symbols.

Also, if you reload the driver with modifications, and don’t update the
symbols, I’ve found that it can sometimes leave the breakpoint at some other
place than where you wanted it, which can cause all sorts of weird
behaviour, including crashes. Best way to avoid this is that your update
script that puts the new binary on the target machine also updates the .PDB
file. Since the .PDB file is locked by WinDBG having it open, you may need
to rename the .PDB to something else (.DELETEME for instance) and then copy
the new file. It’s a valid operation to rename an open file, and once you’ve
put the new .PDB in place, do “.reload MYDRIVER.SYS”, and you can delete the
“.deleteme” file (I just delete the “.deleteme” file before I start renaming
and copying).

Hope this helps, otherwise it would be good to know what circumstances the
problem occurs under.

–
Mats

-----Original Message-----
From: Abhijit [mailto:xxxxx@yahoo.com]
Sent: Friday, March 12, 2004 5:47 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Breakpoint (WinDbg)

I have set a break-point using “bu” in WinDbg.
But the break-point doesn’t seems to work always.
The OS is not breaking into the debugger every time (it breaks
sometimes, whereas it is expected to break always). Has anybody
encountered such an irregular behaviour of WinDbg.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@3dlabs.com
To unsubscribe send a blank email to xxxxx@lists.osr.com