[commit] Follow forks on HP-UX 11.xx
Daniel Jacobowitz
drow@false.org
Wed Jul 20 16:35:00 GMT 2005
On Wed, Jul 20, 2005 at 06:29:18PM +0200, Mark Kettenis wrote:
> Hmm yes, spamming the output while following the output doesn't really
> make sense. On the other hand, I think I'd like to see some
> indication that GDB switched to following the child. But we should
> make sure that all platforms that support this print the same message.
> We should really move the printing of those messages into platform
> independent code.
Yes, we should, and the logic to control them.
> And, the testcases for following vfork all rely on following exec. I
> haven't enabled them, or that feature, because the current user
> interface for following exec is so awful - it silently changes which
> binary you're debugging, messes up configured breakpoints, etc etc.
>
> Hmm yes, I noticed that following execs is still disabled. And yes
> the code is a mess. Any objection against removing it completely and
> start afresh.
I'd rather not touch it until we figure out a better interface; it's
mildly useful as an example of where all the hooks would need to go.
Unless it gets in the way, of course.
> I don't recall if you have GNU/Linux systems to test on. If not, let
> me know if you have testsuite changes you want to check with the
> GNU/Linux implementation of fork following.
>
> Trashed the old SuSE on my amd64 box recently, so I'm going to attempt
> installing Fedora Core 4 on it. You know whether that has a recent
> enough kernel that has the fork/vfork following support in it?
It should, unless RH's patches managed to break it; that's happened in
the past, but I think it won't happen again in 2.6.x. Should be fine.
> Anyway, to what extent does following vfork work on Linux? Does it
> work flawlessly, or are there still some issues?
I believe there's a nasty bit if you try to kill both processes while
stopped at a vfork catchpoint, where you'll end up with a zombie. I
haven't tried to reproduce that in at least a year, though, so it may
be gone now. Otherwise it works quite just fine.
--
Daniel Jacobowitz
CodeSourcery, LLC
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