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Re: Crash in tc-m68k.c:md_estimate_size_before_relax()
- From: Nick Clifton <nickc at cambridge dot redhat dot com>
- To: thorpej at wasabisystems dot com
- Cc: binutils at sources dot redhat dot com, amodora at bigpond dot net dot au
- Date: 02 Jan 2002 17:15:30 +0000
- Subject: Re: Crash in tc-m68k.c:md_estimate_size_before_relax()
- References: <20011226101508.B22658@dr-evil>
Hi Jason,
> I've encountered a bug in gas 2.11.93 20011223 that manifests itself
> as a crash in tc-m68k.c:md_estimate_size_before_relax() in the byte
> branch checks (which you touched on 2001-07-03).
>
> The code in question:
>
> sym_frag = symbol_get_frag (fragP->fr_symbol);
> if (S_GET_VALUE (fragP->fr_symbol) == sym_frag->fr_address)
> {
> fragS *l;
>
> for (l = fragP->fr_next; l != sym_frag; l = l->fr_next)
> if (l->fr_fix != 0)
> ^^^^^^^^^
> NULL-pointer deref here
> break;
> if (l == sym_frag)
> fragP->fr_subtype = TAB (TABTYPE (fragP->fr_subtype), SHORT);
I added a test for the NULL pointer and now your test case assembles
without dumping core.
Cheers
Nick