Re: [ 11/83] module: fix out-by-one error in kallsyms
satoru takeuchi writes:
> Hi,
Hi!
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
>> src = (void *)info->hdr + symsect->sh_offset;
>> nsrc = symsect->sh_size / sizeof(*src);
>>
>> + /* strtab always starts with a nul, so offset 0 is the empty string.
>> */
>> + strtab_size = 1;
>> +
>
> I suspect above code sniped is not needed since the size of src[0](always 1)
> is
> counted at the following code("strtab_size += strlen(..) + 1;").
You are correct, on both counts. This was a remnant of the previous
1-based looping.
Here's the fix I have pending.
Thanks!
Rusty.
module: fix one byte kallsyms overallocation.
Since we fixed our kallsyms strtab expansion code in
59ef28b1f14899b10d6b2682c7057ca00a9a3f47 (module: fix out-by-one error
in kallsyms) we now loop from zero, so we don't need to add an extra
byte for the first empty string.
Reported-by: satoru takeuchi
Signed-off-by: Rusty Russell
diff --git a/kernel/module.c b/kernel/module.c
index a1d2ed8..79a526d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2285,7 +2285,7 @@ static void layout_symtab(struct module *mod, struct
load_info *info)
Elf_Shdr *symsect = info->sechdrs + info->index.sym;
Elf_Shdr *strsect = info->sechdrs + info->index.str;
const Elf_Sym *src;
- unsigned int i, nsrc, ndst, strtab_size;
+ unsigned int i, nsrc, ndst, strtab_size = 0;
/* Put symbol section at end of init part of module. */
symsect->sh_flags |= SHF_ALLOC;
@@ -2296,9 +2296,6 @@ static void layout_symtab(struct module *mod, struct
load_info *info)
src = (void *)info->hdr + symsect->sh_offset;
nsrc = symsect->sh_size / sizeof(*src);
- /* strtab always starts with a nul, so offset 0 is the empty string. */
- strtab_size = 1;
-
/* Compute total space required for the core symbols' strtab. */
for (ndst = i = 0; i < nsrc; i++) {
if (i == 0 ||
@@ -2340,7 +2337,6 @@ static void add_kallsyms(struct module *mod, const struct
load_info *info)
mod->core_symtab = dst = mod->module_core + info->symoffs;
mod->core_strtab = s = mod->module_core + info->stroffs;
src = mod->symtab;
- *s++ = 0;
for (ndst = i = 0; i < mod->num_symtab; i++) {
if (i == 0 ||
is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
--
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Re: [ 11/83] module: fix out-by-one error in kallsyms
satoru takeuchi satoru.takeu...@gmail.com writes:
Hi,
Hi!
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
src = (void *)info-hdr + symsect-sh_offset;
nsrc = symsect-sh_size / sizeof(*src);
+ /* strtab always starts with a nul, so offset 0 is the empty string.
*/
+ strtab_size = 1;
+
I suspect above code sniped is not needed since the size of src[0](always 1)
is
counted at the following code(strtab_size += strlen(..) + 1;).
You are correct, on both counts. This was a remnant of the previous
1-based looping.
Here's the fix I have pending.
Thanks!
Rusty.
module: fix one byte kallsyms overallocation.
Since we fixed our kallsyms strtab expansion code in
59ef28b1f14899b10d6b2682c7057ca00a9a3f47 (module: fix out-by-one error
in kallsyms) we now loop from zero, so we don't need to add an extra
byte for the first empty string.
Reported-by: satoru takeuchi satoru.takeu...@gmail.com
Signed-off-by: Rusty Russell ru...@rustcorp.com.au
diff --git a/kernel/module.c b/kernel/module.c
index a1d2ed8..79a526d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2285,7 +2285,7 @@ static void layout_symtab(struct module *mod, struct
load_info *info)
Elf_Shdr *symsect = info-sechdrs + info-index.sym;
Elf_Shdr *strsect = info-sechdrs + info-index.str;
const Elf_Sym *src;
- unsigned int i, nsrc, ndst, strtab_size;
+ unsigned int i, nsrc, ndst, strtab_size = 0;
/* Put symbol section at end of init part of module. */
symsect-sh_flags |= SHF_ALLOC;
@@ -2296,9 +2296,6 @@ static void layout_symtab(struct module *mod, struct
load_info *info)
src = (void *)info-hdr + symsect-sh_offset;
nsrc = symsect-sh_size / sizeof(*src);
- /* strtab always starts with a nul, so offset 0 is the empty string. */
- strtab_size = 1;
-
/* Compute total space required for the core symbols' strtab. */
for (ndst = i = 0; i nsrc; i++) {
if (i == 0 ||
@@ -2340,7 +2337,6 @@ static void add_kallsyms(struct module *mod, const struct
load_info *info)
mod-core_symtab = dst = mod-module_core + info-symoffs;
mod-core_strtab = s = mod-module_core + info-stroffs;
src = mod-symtab;
- *s++ = 0;
for (ndst = i = 0; i mod-num_symtab; i++) {
if (i == 0 ||
is_core_symbol(src+i, info-sechdrs, info-hdr-e_shnum)) {
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Re: [ 11/83] module: fix out-by-one error in kallsyms
On Fri, Nov 23, 2012 at 07:35:36PM +0900, satoru takeuchi wrote:
> Hi,
>
> 2012/11/22 Greg Kroah-Hartman :
> > 3.6-stable review patch. If anyone has any objections, please let me know.
> >
> > --
> >
> > From: Rusty Russell
> >
> > commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream.
> >
> > Masaki found and patched a kallsyms issue: the last symbol in a
> > module's symtab wasn't transferred. This is because we manually copy
> > the zero'th entry (which is always empty) then copy the rest in a loop
> > starting at 1, though from src[0]. His fix was minimal, I prefer to
> > rewrite the loops in more standard form.
> >
> > There are two loops: one to get the size, and one to copy. Make these
> > identical: always count entry 0 and any defined symbol in an allocated
> > non-init section.
> >
> > This bug exists since the following commit was introduced.
> >module: reduce symbol table for loaded modules (v2)
> >commit: 4a4962263f07d14660849ec134ee42b63e95ea9a
> >
> > LKML: http://lkml.org/lkml/2012/10/24/27
> > Reported-by: Masaki Kimura
> > Signed-off-by: Rusty Russell
> > Signed-off-by: Greg Kroah-Hartman
> >
> > ---
> > kernel/module.c | 27 ---
> > 1 file changed, 16 insertions(+), 11 deletions(-)
> >
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
> > src = (void *)info->hdr + symsect->sh_offset;
> > nsrc = symsect->sh_size / sizeof(*src);
> >
> > + /* strtab always starts with a nul, so offset 0 is the empty
> > string. */
> > + strtab_size = 1;
> > +
>
> I suspect above code sniped is not needed since the size of src[0](always 1)
> is
> counted at the following code("strtab_size += strlen(..) + 1;").
>
> > /* Compute total space required for the core symbols' strtab. */
> > - for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src)
> > - if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum))
> > {
> > - strtab_size += strlen(>strtab[src->st_name])
> > + 1;
> > + for (ndst = i = 0; i < nsrc; i++) {
> > + if (i == 0 ||
> > + is_core_symbol(src+i, info->sechdrs,
> > info->hdr->e_shnum)) {
>
> src[i] rather than src+1 is better as kallsyms();
>
> > + strtab_size +=
> > strlen(>strtab[src[i].st_name])+1;
> > ndst++;
> > }
> > + }
> >
> > /* Append room for core symbols at end of core part. */
> > info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
> > @@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module *
> > mod->core_symtab = dst = mod->module_core + info->symoffs;
> > mod->core_strtab = s = mod->module_core + info->stroffs;
> > src = mod->symtab;
> > - *dst = *src;
> > *s++ = 0;
>
> This "*s++"line is also not needed since the content of src[0] is copied in
> the
> following loop.
>
> If my understanding is correct, the allsym table becomes as follows by
> applying this patch.
>
> ==
> \0\0\0\0... # "\0" means null
> character in this case
> ==
>
> It should be as follows.
>
>
> \0\0\0...
>
>
> This patch would work, but need extra one byte per module. Olease let
> us know if I misunderstand something.
> I didn't confirm with real machine.
Please confirm with a real machine, and if the problem is there, please
submit a patch to get it changed in Linus's tree, which is where this
patch came from.
thanks,
greg k-h
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Re: [ 11/83] module: fix out-by-one error in kallsyms
On Fri, Nov 23, 2012 at 07:35:36PM +0900, satoru takeuchi wrote:
Hi,
2012/11/22 Greg Kroah-Hartman gre...@linuxfoundation.org:
3.6-stable review patch. If anyone has any objections, please let me know.
--
From: Rusty Russell ru...@rustcorp.com.au
commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream.
Masaki found and patched a kallsyms issue: the last symbol in a
module's symtab wasn't transferred. This is because we manually copy
the zero'th entry (which is always empty) then copy the rest in a loop
starting at 1, though from src[0]. His fix was minimal, I prefer to
rewrite the loops in more standard form.
There are two loops: one to get the size, and one to copy. Make these
identical: always count entry 0 and any defined symbol in an allocated
non-init section.
This bug exists since the following commit was introduced.
module: reduce symbol table for loaded modules (v2)
commit: 4a4962263f07d14660849ec134ee42b63e95ea9a
LKML: http://lkml.org/lkml/2012/10/24/27
Reported-by: Masaki Kimura masaki.kimura...@hitachi.com
Signed-off-by: Rusty Russell ru...@rustcorp.com.au
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
---
kernel/module.c | 27 ---
1 file changed, 16 insertions(+), 11 deletions(-)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
src = (void *)info-hdr + symsect-sh_offset;
nsrc = symsect-sh_size / sizeof(*src);
+ /* strtab always starts with a nul, so offset 0 is the empty
string. */
+ strtab_size = 1;
+
I suspect above code sniped is not needed since the size of src[0](always 1)
is
counted at the following code(strtab_size += strlen(..) + 1;).
/* Compute total space required for the core symbols' strtab. */
- for (ndst = i = strtab_size = 1; i nsrc; ++i, ++src)
- if (is_core_symbol(src, info-sechdrs, info-hdr-e_shnum))
{
- strtab_size += strlen(info-strtab[src-st_name])
+ 1;
+ for (ndst = i = 0; i nsrc; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info-sechdrs,
info-hdr-e_shnum)) {
src[i] rather than src+1 is better as kallsyms();
+ strtab_size +=
strlen(info-strtab[src[i].st_name])+1;
ndst++;
}
+ }
/* Append room for core symbols at end of core part. */
info-symoffs = ALIGN(mod-core_size, symsect-sh_addralign ?: 1);
@@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module *
mod-core_symtab = dst = mod-module_core + info-symoffs;
mod-core_strtab = s = mod-module_core + info-stroffs;
src = mod-symtab;
- *dst = *src;
*s++ = 0;
This *s++line is also not needed since the content of src[0] is copied in
the
following loop.
If my understanding is correct, the allsym table becomes as follows by
applying this patch.
==
\0\0first core symbol\0second core symbol\0... # \0 means null
character in this case
==
It should be as follows.
\0first core symbol\0second core symbol\0...
This patch would work, but need extra one byte per module. Olease let
us know if I misunderstand something.
I didn't confirm with real machine.
Please confirm with a real machine, and if the problem is there, please
submit a patch to get it changed in Linus's tree, which is where this
patch came from.
thanks,
greg k-h
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [ 11/83] module: fix out-by-one error in kallsyms
Hi,
2012/11/22 Greg Kroah-Hartman :
> 3.6-stable review patch. If anyone has any objections, please let me know.
>
> --
>
> From: Rusty Russell
>
> commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream.
>
> Masaki found and patched a kallsyms issue: the last symbol in a
> module's symtab wasn't transferred. This is because we manually copy
> the zero'th entry (which is always empty) then copy the rest in a loop
> starting at 1, though from src[0]. His fix was minimal, I prefer to
> rewrite the loops in more standard form.
>
> There are two loops: one to get the size, and one to copy. Make these
> identical: always count entry 0 and any defined symbol in an allocated
> non-init section.
>
> This bug exists since the following commit was introduced.
>module: reduce symbol table for loaded modules (v2)
>commit: 4a4962263f07d14660849ec134ee42b63e95ea9a
>
> LKML: http://lkml.org/lkml/2012/10/24/27
> Reported-by: Masaki Kimura
> Signed-off-by: Rusty Russell
> Signed-off-by: Greg Kroah-Hartman
>
> ---
> kernel/module.c | 27 ---
> 1 file changed, 16 insertions(+), 11 deletions(-)
>
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
> src = (void *)info->hdr + symsect->sh_offset;
> nsrc = symsect->sh_size / sizeof(*src);
>
> + /* strtab always starts with a nul, so offset 0 is the empty string.
> */
> + strtab_size = 1;
> +
I suspect above code sniped is not needed since the size of src[0](always 1) is
counted at the following code("strtab_size += strlen(..) + 1;").
> /* Compute total space required for the core symbols' strtab. */
> - for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src)
> - if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) {
> - strtab_size += strlen(>strtab[src->st_name]) +
> 1;
> + for (ndst = i = 0; i < nsrc; i++) {
> + if (i == 0 ||
> + is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum))
> {
src[i] rather than src+1 is better as kallsyms();
> + strtab_size +=
> strlen(>strtab[src[i].st_name])+1;
> ndst++;
> }
> + }
>
> /* Append room for core symbols at end of core part. */
> info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
> @@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module *
> mod->core_symtab = dst = mod->module_core + info->symoffs;
> mod->core_strtab = s = mod->module_core + info->stroffs;
> src = mod->symtab;
> - *dst = *src;
> *s++ = 0;
This "*s++"line is also not needed since the content of src[0] is copied in the
following loop.
If my understanding is correct, the allsym table becomes as follows by
applying this patch.
==
\0\0\0\0... # "\0" means null
character in this case
==
It should be as follows.
\0\0\0...
This patch would work, but need extra one byte per module. Olease let
us know if I misunderstand something.
I didn't confirm with real machine.
Thanks,
Satoru
> - for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) {
> - if (!is_core_symbol(src, info->sechdrs, info->hdr->e_shnum))
> - continue;
> -
> - dst[ndst] = *src;
> - dst[ndst++].st_name = s - mod->core_strtab;
> - s += strlcpy(s, >strtab[src->st_name], KSYM_NAME_LEN) +
> 1;
> + for (ndst = i = 0; i < mod->num_symtab; i++) {
> + if (i == 0 ||
> + is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum))
> {
> + dst[ndst] = src[i];
> + dst[ndst++].st_name = s - mod->core_strtab;
> + s += strlcpy(s, >strtab[src[i].st_name],
> +KSYM_NAME_LEN) + 1;
> + }
> }
> mod->core_num_syms = ndst;
> }
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe stable" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
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Please read the FAQ at http://www.tux.org/lkml/
Re: [ 11/83] module: fix out-by-one error in kallsyms
Hi,
2012/11/22 Greg Kroah-Hartman gre...@linuxfoundation.org:
3.6-stable review patch. If anyone has any objections, please let me know.
--
From: Rusty Russell ru...@rustcorp.com.au
commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream.
Masaki found and patched a kallsyms issue: the last symbol in a
module's symtab wasn't transferred. This is because we manually copy
the zero'th entry (which is always empty) then copy the rest in a loop
starting at 1, though from src[0]. His fix was minimal, I prefer to
rewrite the loops in more standard form.
There are two loops: one to get the size, and one to copy. Make these
identical: always count entry 0 and any defined symbol in an allocated
non-init section.
This bug exists since the following commit was introduced.
module: reduce symbol table for loaded modules (v2)
commit: 4a4962263f07d14660849ec134ee42b63e95ea9a
LKML: http://lkml.org/lkml/2012/10/24/27
Reported-by: Masaki Kimura masaki.kimura...@hitachi.com
Signed-off-by: Rusty Russell ru...@rustcorp.com.au
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
---
kernel/module.c | 27 ---
1 file changed, 16 insertions(+), 11 deletions(-)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
src = (void *)info-hdr + symsect-sh_offset;
nsrc = symsect-sh_size / sizeof(*src);
+ /* strtab always starts with a nul, so offset 0 is the empty string.
*/
+ strtab_size = 1;
+
I suspect above code sniped is not needed since the size of src[0](always 1) is
counted at the following code(strtab_size += strlen(..) + 1;).
/* Compute total space required for the core symbols' strtab. */
- for (ndst = i = strtab_size = 1; i nsrc; ++i, ++src)
- if (is_core_symbol(src, info-sechdrs, info-hdr-e_shnum)) {
- strtab_size += strlen(info-strtab[src-st_name]) +
1;
+ for (ndst = i = 0; i nsrc; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info-sechdrs, info-hdr-e_shnum))
{
src[i] rather than src+1 is better as kallsyms();
+ strtab_size +=
strlen(info-strtab[src[i].st_name])+1;
ndst++;
}
+ }
/* Append room for core symbols at end of core part. */
info-symoffs = ALIGN(mod-core_size, symsect-sh_addralign ?: 1);
@@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module *
mod-core_symtab = dst = mod-module_core + info-symoffs;
mod-core_strtab = s = mod-module_core + info-stroffs;
src = mod-symtab;
- *dst = *src;
*s++ = 0;
This *s++line is also not needed since the content of src[0] is copied in the
following loop.
If my understanding is correct, the allsym table becomes as follows by
applying this patch.
==
\0\0first core symbol\0second core symbol\0... # \0 means null
character in this case
==
It should be as follows.
\0first core symbol\0second core symbol\0...
This patch would work, but need extra one byte per module. Olease let
us know if I misunderstand something.
I didn't confirm with real machine.
Thanks,
Satoru
- for (ndst = i = 1; i mod-num_symtab; ++i, ++src) {
- if (!is_core_symbol(src, info-sechdrs, info-hdr-e_shnum))
- continue;
-
- dst[ndst] = *src;
- dst[ndst++].st_name = s - mod-core_strtab;
- s += strlcpy(s, mod-strtab[src-st_name], KSYM_NAME_LEN) +
1;
+ for (ndst = i = 0; i mod-num_symtab; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info-sechdrs, info-hdr-e_shnum))
{
+ dst[ndst] = src[i];
+ dst[ndst++].st_name = s - mod-core_strtab;
+ s += strlcpy(s, mod-strtab[src[i].st_name],
+KSYM_NAME_LEN) + 1;
+ }
}
mod-core_num_syms = ndst;
}
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Please read the FAQ at http://www.tux.org/lkml/
[ 11/83] module: fix out-by-one error in kallsyms
3.6-stable review patch. If anyone has any objections, please let me know.
--
From: Rusty Russell
commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream.
Masaki found and patched a kallsyms issue: the last symbol in a
module's symtab wasn't transferred. This is because we manually copy
the zero'th entry (which is always empty) then copy the rest in a loop
starting at 1, though from src[0]. His fix was minimal, I prefer to
rewrite the loops in more standard form.
There are two loops: one to get the size, and one to copy. Make these
identical: always count entry 0 and any defined symbol in an allocated
non-init section.
This bug exists since the following commit was introduced.
module: reduce symbol table for loaded modules (v2)
commit: 4a4962263f07d14660849ec134ee42b63e95ea9a
LKML: http://lkml.org/lkml/2012/10/24/27
Reported-by: Masaki Kimura
Signed-off-by: Rusty Russell
Signed-off-by: Greg Kroah-Hartman
---
kernel/module.c | 27 ---
1 file changed, 16 insertions(+), 11 deletions(-)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
src = (void *)info->hdr + symsect->sh_offset;
nsrc = symsect->sh_size / sizeof(*src);
+ /* strtab always starts with a nul, so offset 0 is the empty string. */
+ strtab_size = 1;
+
/* Compute total space required for the core symbols' strtab. */
- for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src)
- if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) {
- strtab_size += strlen(>strtab[src->st_name]) + 1;
+ for (ndst = i = 0; i < nsrc; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
+ strtab_size += strlen(>strtab[src[i].st_name])+1;
ndst++;
}
+ }
/* Append room for core symbols at end of core part. */
info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
@@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module *
mod->core_symtab = dst = mod->module_core + info->symoffs;
mod->core_strtab = s = mod->module_core + info->stroffs;
src = mod->symtab;
- *dst = *src;
*s++ = 0;
- for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) {
- if (!is_core_symbol(src, info->sechdrs, info->hdr->e_shnum))
- continue;
-
- dst[ndst] = *src;
- dst[ndst++].st_name = s - mod->core_strtab;
- s += strlcpy(s, >strtab[src->st_name], KSYM_NAME_LEN) + 1;
+ for (ndst = i = 0; i < mod->num_symtab; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
+ dst[ndst] = src[i];
+ dst[ndst++].st_name = s - mod->core_strtab;
+ s += strlcpy(s, >strtab[src[i].st_name],
+KSYM_NAME_LEN) + 1;
+ }
}
mod->core_num_syms = ndst;
}
--
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[ 11/83] module: fix out-by-one error in kallsyms
3.6-stable review patch. If anyone has any objections, please let me know.
--
From: Rusty Russell ru...@rustcorp.com.au
commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream.
Masaki found and patched a kallsyms issue: the last symbol in a
module's symtab wasn't transferred. This is because we manually copy
the zero'th entry (which is always empty) then copy the rest in a loop
starting at 1, though from src[0]. His fix was minimal, I prefer to
rewrite the loops in more standard form.
There are two loops: one to get the size, and one to copy. Make these
identical: always count entry 0 and any defined symbol in an allocated
non-init section.
This bug exists since the following commit was introduced.
module: reduce symbol table for loaded modules (v2)
commit: 4a4962263f07d14660849ec134ee42b63e95ea9a
LKML: http://lkml.org/lkml/2012/10/24/27
Reported-by: Masaki Kimura masaki.kimura...@hitachi.com
Signed-off-by: Rusty Russell ru...@rustcorp.com.au
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
---
kernel/module.c | 27 ---
1 file changed, 16 insertions(+), 11 deletions(-)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2273,12 +2273,17 @@ static void layout_symtab(struct module
src = (void *)info-hdr + symsect-sh_offset;
nsrc = symsect-sh_size / sizeof(*src);
+ /* strtab always starts with a nul, so offset 0 is the empty string. */
+ strtab_size = 1;
+
/* Compute total space required for the core symbols' strtab. */
- for (ndst = i = strtab_size = 1; i nsrc; ++i, ++src)
- if (is_core_symbol(src, info-sechdrs, info-hdr-e_shnum)) {
- strtab_size += strlen(info-strtab[src-st_name]) + 1;
+ for (ndst = i = 0; i nsrc; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info-sechdrs, info-hdr-e_shnum)) {
+ strtab_size += strlen(info-strtab[src[i].st_name])+1;
ndst++;
}
+ }
/* Append room for core symbols at end of core part. */
info-symoffs = ALIGN(mod-core_size, symsect-sh_addralign ?: 1);
@@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module *
mod-core_symtab = dst = mod-module_core + info-symoffs;
mod-core_strtab = s = mod-module_core + info-stroffs;
src = mod-symtab;
- *dst = *src;
*s++ = 0;
- for (ndst = i = 1; i mod-num_symtab; ++i, ++src) {
- if (!is_core_symbol(src, info-sechdrs, info-hdr-e_shnum))
- continue;
-
- dst[ndst] = *src;
- dst[ndst++].st_name = s - mod-core_strtab;
- s += strlcpy(s, mod-strtab[src-st_name], KSYM_NAME_LEN) + 1;
+ for (ndst = i = 0; i mod-num_symtab; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info-sechdrs, info-hdr-e_shnum)) {
+ dst[ndst] = src[i];
+ dst[ndst++].st_name = s - mod-core_strtab;
+ s += strlcpy(s, mod-strtab[src[i].st_name],
+KSYM_NAME_LEN) + 1;
+ }
}
mod-core_num_syms = ndst;
}
--
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