This is the mail archive of the
gdb-patches@sources.redhat.com
mailing list for the GDB project.
Re: [RFA] Avoid segfault in decode_line_2
Elena Zannoni writes:
> Michal Ludvig writes:
> > Hi all,
> > this patch fixes a problem that I met while debugging a testsuite
> > failure on amd64:
> >
> > > Running gdb-head/gdb/testsuite/gdb.c++/templates.exp ...
> > > FAIL: gdb.c++/templates.exp: constructor breakpoint (timeout)
> >
> > (gdb) break T5<int>::T5
> > -> Segfault in linespec.c:486 [decode_line_2()] because
> > values.sals[i].symtab is NULL and dereferencing of
> > values.sals[i].symtab->filename crashes.
> >
> > After some investigation I found out that .debug_line section of the
> > input file was broken (reported to binutils@ list).
> > However broken debug info is not an excuse for GDB to crash.
> >
> > OK to apply to head and branch?
> >
> > Michal Ludvig
> > --
> > * SuSE CR, s.r.o * mludvig@suse.cz
> > * (+420) 296.545.373 * http://www.suse.cz
> > 2003-07-11 Michal Ludvig <mludvig@suse.cz>
> >
> > * linespec.c (decode_line_2): Avoid crash if
> > find_function_start_sal() returns empty record.
> >
> > Index: linespec.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/linespec.c,v
> > retrieving revision 1.49
> > diff -u -p -r1.49 linespec.c
> > --- linespec.c 8 Jun 2003 18:27:13 -0000 1.49
> > +++ linespec.c 11 Jul 2003 06:59:01 -0000
> > @@ -483,11 +483,16 @@ decode_line_2 (struct symbol *sym_arr[],
> > if (sym_arr[i] && SYMBOL_CLASS (sym_arr[i]) == LOC_BLOCK)
> > {
> > values.sals[i] = find_function_start_sal (sym_arr[i], funfirstline);
> > - printf_unfiltered ("[%d] %s at %s:%d\n",
> > + printf_unfiltered ("[%d] %s at %s:%d ",
> > (i + 2),
> > SYMBOL_PRINT_NAME (sym_arr[i]),
> > - values.sals[i].symtab->filename,
> > + values.sals[i].symtab ?
> > + values.sals[i].symtab->filename :
> > + "?FILE",
> > values.sals[i].line);
> > + if (! values.sals[i].symtab)
> > + printf_unfiltered ("[No symtab? Probably a broken debug info...]" );
> > + printf_unfiltered ("\n");
> > }
> > else
> > printf_unfiltered ("?HERE\n");
>
> Yes, but, could you change this to use an if (values.sals[i].symtab)
> before the printf_filtered and avoid the conditional expression? You
> will end up getting rid of the if() for the No symtab?.. case as well,
> since that can be folded into a single printf.
>
> elena
I checked in the following:
2003-07-23 Michal Ludvig <mludvig@suse.cz>
Elena Zannoni <ezannoni@redhat.com>
* linespec.c (decode_line_2): Avoid crash if
find_function_start_sal() returns empty record.
Index: linespec.c
===================================================================
RCS file: /cvs/uberbaum/gdb/linespec.c,v
retrieving revision 1.49
diff -u -p -r1.49 linespec.c
--- linespec.c 8 Jun 2003 18:27:13 -0000 1.49
+++ linespec.c 23 Jul 2003 19:20:14 -0000
@@ -483,11 +483,18 @@ decode_line_2 (struct symbol *sym_arr[],
if (sym_arr[i] && SYMBOL_CLASS (sym_arr[i]) == LOC_BLOCK)
{
values.sals[i] = find_function_start_sal (sym_arr[i], funfirstline);
- printf_unfiltered ("[%d] %s at %s:%d\n",
- (i + 2),
- SYMBOL_PRINT_NAME (sym_arr[i]),
- values.sals[i].symtab->filename,
- values.sals[i].line);
+ if (values.sals[i].symtab)
+ printf_unfiltered ("[%d] %s at %s:%d\n",
+ (i + 2),
+ SYMBOL_PRINT_NAME (sym_arr[i]),
+ values.sals[i].symtab->filename,
+ values.sals[i].line);
+ else
+ printf_unfiltered ("[%d] %s at ?FILE:%d [No symtab? Probably broken debug info...]\n",
+ (i + 2),
+ SYMBOL_PRINT_NAME (sym_arr[i]),
+ values.sals[i].line);
+
}
else
printf_unfiltered ("?HERE\n");