[Karmic] SRU: Upstream detected regression in 2.6.31.7 (re-send)

Colin Ian King colin.king at canonical.com
Mon Jan 25 11:35:44 UTC 2010


On Fri, 2010-01-22 at 12:15 +0100, Stefan Bader wrote:
> Resending the patch as it now has hit both upstream and 2.6.32.y.
> Unfortunately 2.6.31.y support ended by now.
> 
> -Stefan
> 
> From 8dfabfcf7b0c03f33f7cb945772027060de70b61 Mon Sep 17 00:00:00 2001
> From: Ben Hutchings <ben at decadent.org.uk>
> Date: Sat, 19 Dec 2009 14:43:01 +0000
> Subject: [PATCH] modules: Skip empty sections when exporting section notes
> 
> BugLink: http://bugs.launchpad.net/bugs/511129
> 
> commit 10b465aaf9536ee5a16652fa0700740183d48ec9 upstream.
> 
> Commit 35dead4 "modules: don't export section names of empty sections
> via sysfs" changed the set of sections that have attributes, but did
> not change the iteration over these attributes in add_notes_attrs().
> This can lead to add_notes_attrs() creating attributes with the wrong
> names or with null name pointers.
> 
> Introduce a sect_empty() function and use it in both add_sect_attrs()
> and add_notes_attrs().
> 
> Reported-by: Martin Michlmayr <tbm at cyrius.com>
> Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
> Tested-by: Martin Michlmayr <tbm at cyrius.com>
> Signed-off-by: Rusty Russell <rusty at rustcorp.com.au>
> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
> Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
> Acked-by: Leann Ogasawara <leann.ogasawara at canonical.com>
> ---
>  kernel/module.c |   17 ++++++++++-------
>  1 files changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/module.c b/kernel/module.c
> index 5842a71..37caef0 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -1146,6 +1146,12 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
>   * J. Corbet <corbet at lwn.net>
>   */
>  #if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS)
> +
> +static inline bool sect_empty(const Elf_Shdr *sect)
> +{
> +	return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
> +}
> +
>  struct module_sect_attr
>  {
>  	struct module_attribute mattr;
> @@ -1187,8 +1193,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
>  
>  	/* Count loaded sections and allocate structures */
>  	for (i = 0; i < nsect; i++)
> -		if (sechdrs[i].sh_flags & SHF_ALLOC
> -		    && sechdrs[i].sh_size)
> +		if (!sect_empty(&sechdrs[i]))
>  			nloaded++;
>  	size[0] = ALIGN(sizeof(*sect_attrs)
>  			+ nloaded * sizeof(sect_attrs->attrs[0]),
> @@ -1206,9 +1211,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
>  	sattr = &sect_attrs->attrs[0];
>  	gattr = &sect_attrs->grp.attrs[0];
>  	for (i = 0; i < nsect; i++) {
> -		if (! (sechdrs[i].sh_flags & SHF_ALLOC))
> -			continue;
> -		if (!sechdrs[i].sh_size)
> +		if (sect_empty(&sechdrs[i]))
>  			continue;
>  		sattr->address = sechdrs[i].sh_addr;
>  		sattr->name = kstrdup(secstrings + sechdrs[i].sh_name,
> @@ -1292,7 +1295,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
>  	/* Count notes sections and allocate structures.  */
>  	notes = 0;
>  	for (i = 0; i < nsect; i++)
> -		if ((sechdrs[i].sh_flags & SHF_ALLOC) &&
> +		if (!sect_empty(&sechdrs[i]) &&
>  		    (sechdrs[i].sh_type == SHT_NOTE))
>  			++notes;
>  
> @@ -1308,7 +1311,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
>  	notes_attrs->notes = notes;
>  	nattr = &notes_attrs->attrs[0];
>  	for (loaded = i = 0; i < nsect; ++i) {
> -		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
> +		if (sect_empty(&sechdrs[i]))
>  			continue;
>  		if (sechdrs[i].sh_type == SHT_NOTE) {
>  			nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
> -- 
> 1.6.3.3
> 
> 
Looks reasonable to me and sect_empty() makes the code clearer too.

Acked-by: Colin King <colin.king at canonical.com>






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