This is the mail archive of the
mailing list for the glibc project.
Re: [PATCH] Ensure DSO_FILENAME does not dereference NULL.
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: Marcus Shawcroft <marcus dot shawcroft at linaro dot org>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 12 Nov 2013 23:32:23 -0500
- Subject: Re: [PATCH] Ensure DSO_FILENAME does not dereference NULL.
- Authentication-results: sourceware.org; auth=none
- References: <CABXK9ndMvnpRArWGU4-JWgiePLOXNs74AuK9C6dm0J1Gyu+k_A at mail dot gmail dot com>
On 11/12/2013 10:24 AM, Marcus Shawcroft wrote:
> The AArch64 and ARM glibc build is currently broken for trunk gcc.
> Both builds fail with link errors for the multiple definition of
> This is caused by the "Isolate erroneous paths optimization" patch
> recently added to gcc here:
> One effect of this patch is to replace unreachable paths with a call to abort().
> There is code in _dl_lookup_symbol_x() which may pass NULL to
> DSO_FILENAME(). This macro always dereferences the filename. The
> isolate erroneous paths cod in gcc inserts an abort() in place of the
> ill defined code. The linker subsequently pulls in a bunch of code
> from libpic.a, including the alternative definition of
> The convention elsewhere appears to be to pass "" rather than NULL.
> This patch seems obvious to me, I'll commit it tomorrow unless anyone
I've reviewed the relevant macro and code and I agree. Your analysis
> * elf/dl-lookup.c (_dl_lookup_symbol_x): Pass "" instead of NULL to
Please use correct GNU ChangeLog format in your patch postings.
2013-11-12 Marcus Shawcroft <firstname.lastname@example.org>
* elf/dl-lookup.c (_dl_lookup_symbol_x): If UNDEF_MAP is false
set reference_name to "" to avoid passing NULL to DSO_FILENAME.
> diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
> index 39f463e..f869dcf 100644
> --- a/elf/dl-lookup.c
> +++ b/elf/dl-lookup.c
> @@ -746,7 +746,7 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
> contain the needed symbol. This code is never reached
> for unversioned lookups. */
> assert (version != NULL);
> - const char *reference_name = undef_map ? undef_map->l_name : NULL;
> + const char *reference_name = undef_map ? undef_map->l_name : "";
> /* XXX We cannot translate the message. */
> _dl_signal_cerror (0, DSO_FILENAME (reference_name),
> -- 22.214.171.124