[Crash-utility] Patch to fix Seg Violation in parse_for_member

[Dave Anderson]

----- Original Message -----
> 
> 
> ----- Original Message -----
> > What about replacing that fprintf() with fprintf(pc->saved_fp, "%s", buf)
> > or even fputs(buf, pc->saved_fp)?
> 
> Hmmm, that would be preferable -- let me test that...

Both options work as expected -- I'll go with the former.

Thanks Adrien,
  Dave

> > On Fri, Aug 10, 2012 at 2:55 PM, Dave Anderson
> > <anderson at redhat.com>
> > wrote:
> > >
> > >
> > > ----- Original Message -----
> > >> On Thu, 2012-08-09 at 16:23 -0600, Bob Montgomery wrote:
> > >> > If you change the
> > >> >      fprintf(pc->saved_fp, buf);
> > >> > lines to
> > >> >      print_verbatim(pc->saved_fp, buf);
> > >> >
> > >> > Then I won't get:
> > >> >
> > >> > crash> sk_buff.head ffff88012014dc80
> > >> > Segmentation fault
> > >> >
> > >> > When I need to get:
> > >> >
> > >> > crash> sk_buff.head ffff88012014dc80
> > >> >   head = 0xffff880121267000 "\"%s %s %s\", got type \"%s\""
> > >> >
> > >> >
> > >> > Patch attached (6.0.8).
> > >> >
> > >> > I suspect performance will suffer a bit when I try to print
> > >> > 2 million of these...
> > >>
> > >> Wonder if it would be quicker on average to string search for
> > >> "%"
> > >> and
> > >> conditionally call print_verbatim???  I had lots of successful
> > >> fprintf's and only a small number of seg viol cases.
> > >>
> > >> Bob M.
> > >
> > > Hi Bob,
> > >
> > > Although in practice,
> > >
> > >  (1) parse_for_member() is rarely called "in quantity", and
> > >  (2) when it is called, it would only encounter this with "char
> > >  *"
> > >  members, and
> > >  (3) the string would also have to have a '%' in it.
> > >
> > > On the other hand, if you test the two print-types with a million
> > > calls,
> > > there's a significant performance hit.  But if a strstr() is done
> > > first
> > > on the string, there's virtually no hit at all if there's no '%'
> > > in
> > > it.
> > >
> > > So yes, I agree with you that the string-search/conditional call
> > > should be done.
> > > I'll add that to your patch, and queue it for crash-6.0.9.
> > >
> > > Thanks,
> > >   Dave
> > >
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> > 
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>