| Message ID | 1261415196-15326-1-git-send-email-stefan.bader@canonical.com |
|---|---|
| State | Superseded |
| Delegated to: | Stefan Bader |
| Headers | show |
On Mon, 2009-12-21 at 18:06 +0100, Stefan Bader wrote: > 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 Acked-by: Leann Ogasawara <leann.ogasawara@canonical.com> > --- > > > Subject: [PATCH] modules: Skip empty sections when exporting section notes > From: Ben Hutchings <ben@decadent.org.uk> > Date: Sat, 19 Dec 2009 14:43:01 +0000 > To: Rusty Russell <rusty@rustcorp.com.au> > CC: Helge Deller <deller@gmx.de>, Martin Michlmayr <tbm@cyrius.com>, LKML <linux-kernel@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@cyrius.com> > Signed-off-by: Ben Hutchings <ben@decadent.org.uk> > Tested-by: Martin Michlmayr <tbm@cyrius.com> > Cc: stable@kernel.org > Signed-off-by: Stefan Bader <stefan.bader@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@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; > -- >
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@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;