lkml.org 
[lkml]   [2007]   [Feb]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 0/4] coredump: core dump masking support v3
Date
Markus Gutschke <markus@google.com> wrote:

> > How does it work when you can't actually get back to userspace to have
> > userspace do the coredump? You still have to handle the userspace
> > equivalents of double/triple faults.
>
> My experience shows that there are only very rare occurrences of situations
> where you cannot get back into userspace to do the coredump, and the
> coredumper tries very hard never to cause additional faults.

So what? If they can occur, you have to handle them.

> While I am sure you could construct scenarios where this would happen,
> realistically the only one I have run into were stack overflows, and they can
> be handled by carefully setting up an alternate stack for signal handlers --
> just make sure the entire stack is already dirtied before you run out of
> memory (or, turn of overcommitting).

Duff SIGSEGV or SIGBUS signal handlers are just as realistic. All that takes
is for someone to make a programming error. Remember: error paths are the
least frequently tested.

And any time you say "by carefully setting up" you can guarantee someone's
going to do it wrong.

David
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-02-26 12:53    [from the cache]
©2003-2011 Jasper Spaans