[Karmic] SRU: Upstream detected regression in 2.6.31.7
Stefan Bader
stefan.bader at canonical.com
Mon Dec 21 17:06:36 UTC 2009
SRU Justification:
Impact: Upstream stable patch apparently introduced a regression with
2.6.31.7 (missed to change one of the affected places).
Fix: This fix was sent to upstream (cc: stable). It is not (yet)
integrated in upstream, but as soon as it does I'd like to pull
that in together with the 2.6.31.7 we are reviewing.
Testcase: see below
---
Subject: [PATCH] modules: Skip empty sections when exporting section notes
From: Ben Hutchings <ben at decadent.org.uk>
Date: Sat, 19 Dec 2009 14:43:01 +0000
To: Rusty Russell <rusty at rustcorp.com.au>
CC: Helge Deller <deller at gmx.de>, Martin Michlmayr <tbm at cyrius.com>, LKML <linux-kernel at vger.kernel.org>
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>
Cc: stable at kernel.org
Signed-off-by: Stefan Bader <stefan.bader 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 e96b8ed..f82386b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1010,6 +1010,12 @@ 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;
@@ -1051,8 +1057,7 @@ 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]),
@@ -1070,9 +1075,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
sattr = §_attrs->attrs[0];
gattr = §_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,
@@ -1156,7 +1159,7 @@ 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;
@@ -1172,7 +1175,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
notes_attrs->notes = notes;
nattr = ¬es_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;
--
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