Re: gdb doesn't work very well with dynamic linked binaries

[James Cownie <jcownie at etnus dot com>]

This threads seems really to have morphed to be about using the
hardware watchpoint registers on IA32.

So :-

Note that there are a couple of linux kernel bugs in 2.2 (one of which
was fixed in 2.2.17) which affect the use of the debug registers.

The first bug (which was fixed in 2.2.17) was that the debug status
register wasn't being saved where it could be seen by ptrace, so if
you were relying on looking at the hardware status register you were
stuffed.

The second (which isn't yet fixed) I described with a test case in a
previous mail here. ( http://sources.redhat.com/ml/gdb/2000-08/msg00072.html )
Basically the kernel ignores all hardware
watchpoints from the point where one of them is triggered inside the
kernel until a reschedule. This means many watchpoints at user level
can be silently skipped :-(

AFAICS both bugs remain in 2.4.0-test7.

-- Jim 

James Cownie	<jcownie@etnus.com>
Etnus, LLC.     +44 117 9071438
http://www.etnus.com



-- 
-- Jim
James Cownie
jcownie@etnus.com
Etnus, Inc.
Phone +44 117 9071438