Re: [RFA] Fix a crash in coffread.c (Was: GDB 6.1 branch 2004-02-26-gmt)

[Elena Zannoni <ezannoni at redhat dot com>]

Eli Zaretskii writes:
 > > Date: Sat, 21 Feb 2004 18:14:41 +0200
 > > From: "Eli Zaretskii" <eliz@elta.co.il>
 > > 
 > > I built today the latest snapshot of CVS HEAD and found a new
 > > regression: the DJGPP port crashes at startup while debugging itself.
 > 
 > Bug squashed, I think.  It turned out to be a very old one, actually;
 > the current CVS HEAD didn't introduce it, it just exposed it because
 > the GDB binary is now so large.
 > 
 > The bug happens only when GDB (or any other large program) is compiled
 > with COFF debug info and the line table overflows the 64K limit
 > allowed by COFF debug info.  I think the patch below fixes that.
 > 
 > Okay to commit?
 > 
 > 2004-02-22  Eli Zaretskii  <eliz@elta.co.il>
 > 
 > 	* coffread.c (enter_linenos): Don't let rawptr reference memory
 > 	outside linetab[]'s limits.
 > 
 > 
 > --- gdb/coffread.c~0	2004-02-14 17:46:32.000000000 +0200
 > +++ gdb/coffread.c	2004-02-22 22:42:34.000000000 +0200
 > @@ -1362,11 +1362,15 @@ enter_linenos (long file_offset, int fir
 >    /* line numbers start at one for the first line of the function */
 >    first_line--;
 >  
 > -  for (;;)
 > +  /* If the line number is full (e.g. 64K lines in COFF debug info),
                    ^^^^^^^^
                     table?

 > +     the next function's L_LNNO32 might not be zero, so don't overstep
 > +     the table's end in any case.  */
 > +  for ( ; rawptr <= &linetab[0] + linetab_size; )

how about a while loop?

I am not sure I understand how the two cases differ in the layout of
the debug info. Is the beginning of a function still zero valued? Do
we have a function with >64k lines? If we are running beyond the end
of the table, does this mean that we don't read all the debug info we
have?

elena