* Modules: Handle symbols that have a zero value
@ 2007-11-21 5:56 Christoph Lameter
2007-11-21 13:38 ` Mathieu Desnoyers
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Lameter @ 2007-11-21 5:56 UTC (permalink / raw)
To: akpm; +Cc: linux-kernel, Kay Sievers, Mathieu Desnoyers
Another issue that I encountered with the cpu_alloc stuff.
The module subsystem cannot handle symbols that are zero. If symbols are
present that have a zero value then the module resolver prints out
a message that these symbols are unresolved.
Use ERR_PTR to return an error code instead of 0. This is a bit awkward
since the addresses are handled as unsigned longs. So we need to convert
them everywhere.
The idea top use ERR_PTR is from Mathieu.
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
---
kernel/module.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
Index: linux-2.6/kernel/module.c
===================================================================
--- linux-2.6.orig/kernel/module.c 2007-11-20 21:06:29.856965949 -0800
+++ linux-2.6/kernel/module.c 2007-11-20 21:16:53.001715887 -0800
@@ -285,7 +285,7 @@ static unsigned long __find_symbol(const
}
}
DEBUGP("Failed to find symbol %s\n", name);
- return 0;
+ return (unsigned long)ERR_PTR(-ENOENT);
}
/* Search for module by name: must hold module_mutex. */
@@ -648,7 +648,7 @@ void __symbol_put(const char *symbol)
const unsigned long *crc;
preempt_disable();
- if (!__find_symbol(symbol, &owner, &crc, 1))
+ if (IS_ERR((void *)__find_symbol(symbol, &owner, &crc, 1)))
BUG();
module_put(owner);
preempt_enable();
@@ -792,7 +792,8 @@ static inline int check_modstruct_versio
const unsigned long *crc;
struct module *owner;
- if (!__find_symbol("struct_module", &owner, &crc, 1))
+ if (IS_ERR((void *)__find_symbol("struct_module",
+ &owner, &crc, 1)))
BUG();
return check_version(sechdrs, versindex, "struct_module", mod,
crc);
@@ -845,7 +846,7 @@ static unsigned long resolve_symbol(Elf_
/* use_module can fail due to OOM, or module unloading */
if (!check_version(sechdrs, versindex, name, mod, crc) ||
!use_module(mod, owner))
- ret = 0;
+ ret = (unsigned long)ERR_PTR(-EINVAL);
}
return ret;
}
@@ -1238,14 +1239,16 @@ static int verify_export_symbols(struct
const unsigned long *crc;
for (i = 0; i < mod->num_syms; i++)
- if (__find_symbol(mod->syms[i].name, &owner, &crc, 1)) {
+ if (!IS_ERR((void *)__find_symbol(mod->syms[i].name,
+ &owner, &crc, 1))) {
name = mod->syms[i].name;
ret = -ENOEXEC;
goto dup;
}
for (i = 0; i < mod->num_gpl_syms; i++)
- if (__find_symbol(mod->gpl_syms[i].name, &owner, &crc, 1)) {
+ if (!IS_ERR((void *)__find_symbol(mod->gpl_syms[i].name,
+ &owner, &crc, 1))) {
name = mod->gpl_syms[i].name;
ret = -ENOEXEC;
goto dup;
@@ -1295,7 +1298,7 @@ static int simplify_symbols(Elf_Shdr *se
strtab + sym[i].st_name, mod);
/* Ok if resolved. */
- if (sym[i].st_value != 0)
+ if (!IS_ERR((void *)sym[i].st_value))
break;
/* Ok if weak. */
if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Modules: Handle symbols that have a zero value
2007-11-21 5:56 Modules: Handle symbols that have a zero value Christoph Lameter
@ 2007-11-21 13:38 ` Mathieu Desnoyers
2007-11-21 21:02 ` Christoph Lameter
0 siblings, 1 reply; 3+ messages in thread
From: Mathieu Desnoyers @ 2007-11-21 13:38 UTC (permalink / raw)
To: Christoph Lameter; +Cc: akpm, linux-kernel, Kay Sievers
* Christoph Lameter (clameter@sgi.com) wrote:
> Another issue that I encountered with the cpu_alloc stuff.
>
>
>
> The module subsystem cannot handle symbols that are zero. If symbols are
> present that have a zero value then the module resolver prints out
> a message that these symbols are unresolved.
>
> Use ERR_PTR to return an error code instead of 0. This is a bit awkward
> since the addresses are handled as unsigned longs. So we need to convert
> them everywhere.
>
> The idea top use ERR_PTR is from Mathieu.
>
I thought these functions were returning a pointer. Well, since they are
simply returning an unsigned long, why not use :
return -ENOENT;
directly ?
(ERR_PTR() in linux/err.h is a simple cast from long to void*).
Mathieu
> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Cc: Kay Sievers <kay.sievers@vrfy.org>
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
>
> ---
> kernel/module.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> Index: linux-2.6/kernel/module.c
> ===================================================================
> --- linux-2.6.orig/kernel/module.c 2007-11-20 21:06:29.856965949 -0800
> +++ linux-2.6/kernel/module.c 2007-11-20 21:16:53.001715887 -0800
> @@ -285,7 +285,7 @@ static unsigned long __find_symbol(const
> }
> }
> DEBUGP("Failed to find symbol %s\n", name);
> - return 0;
> + return (unsigned long)ERR_PTR(-ENOENT);
> }
>
> /* Search for module by name: must hold module_mutex. */
> @@ -648,7 +648,7 @@ void __symbol_put(const char *symbol)
> const unsigned long *crc;
>
> preempt_disable();
> - if (!__find_symbol(symbol, &owner, &crc, 1))
> + if (IS_ERR((void *)__find_symbol(symbol, &owner, &crc, 1)))
> BUG();
> module_put(owner);
> preempt_enable();
> @@ -792,7 +792,8 @@ static inline int check_modstruct_versio
> const unsigned long *crc;
> struct module *owner;
>
> - if (!__find_symbol("struct_module", &owner, &crc, 1))
> + if (IS_ERR((void *)__find_symbol("struct_module",
> + &owner, &crc, 1)))
> BUG();
> return check_version(sechdrs, versindex, "struct_module", mod,
> crc);
> @@ -845,7 +846,7 @@ static unsigned long resolve_symbol(Elf_
> /* use_module can fail due to OOM, or module unloading */
> if (!check_version(sechdrs, versindex, name, mod, crc) ||
> !use_module(mod, owner))
> - ret = 0;
> + ret = (unsigned long)ERR_PTR(-EINVAL);
> }
> return ret;
> }
> @@ -1238,14 +1239,16 @@ static int verify_export_symbols(struct
> const unsigned long *crc;
>
> for (i = 0; i < mod->num_syms; i++)
> - if (__find_symbol(mod->syms[i].name, &owner, &crc, 1)) {
> + if (!IS_ERR((void *)__find_symbol(mod->syms[i].name,
> + &owner, &crc, 1))) {
> name = mod->syms[i].name;
> ret = -ENOEXEC;
> goto dup;
> }
>
> for (i = 0; i < mod->num_gpl_syms; i++)
> - if (__find_symbol(mod->gpl_syms[i].name, &owner, &crc, 1)) {
> + if (!IS_ERR((void *)__find_symbol(mod->gpl_syms[i].name,
> + &owner, &crc, 1))) {
> name = mod->gpl_syms[i].name;
> ret = -ENOEXEC;
> goto dup;
> @@ -1295,7 +1298,7 @@ static int simplify_symbols(Elf_Shdr *se
> strtab + sym[i].st_name, mod);
>
> /* Ok if resolved. */
> - if (sym[i].st_value != 0)
> + if (!IS_ERR((void *)sym[i].st_value))
> break;
> /* Ok if weak. */
> if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Modules: Handle symbols that have a zero value
2007-11-21 13:38 ` Mathieu Desnoyers
@ 2007-11-21 21:02 ` Christoph Lameter
0 siblings, 0 replies; 3+ messages in thread
From: Christoph Lameter @ 2007-11-21 21:02 UTC (permalink / raw)
To: Mathieu Desnoyers; +Cc: akpm, linux-kernel, Kay Sievers
On Wed, 21 Nov 2007, Mathieu Desnoyers wrote:
> return -ENOENT;
>
> directly ?
>
> (ERR_PTR() in linux/err.h is a simple cast from long to void*).
Right and there is also IS_ERR_VALUE. Thanks for the feedback. New
version:
Modules: Handle symbols that have a zero value
The module subsystem cannot handle symbols that are zero. If symbols are
present that have a zero value then the module resolver prints out
a message that these symbols are unresolved.
Use ERR_PTR to return an error code instead of 0. This is a bit awkward
since the addresses are handled as unsigned longs. So we need to convert
them everywhere.
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Kay Sievers <kay.sievers@vrfy.org
Signed-off-by: Christoph Lameter <clameter@sgi.com>
---
kernel/module.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
Index: linux-2.6/kernel/module.c
===================================================================
--- linux-2.6.orig/kernel/module.c 2007-11-21 12:58:33.095608448 -0800
+++ linux-2.6/kernel/module.c 2007-11-21 13:00:30.199108674 -0800
@@ -285,7 +285,7 @@ static unsigned long __find_symbol(const
}
}
DEBUGP("Failed to find symbol %s\n", name);
- return 0;
+ return -ENOENT;
}
/* Search for module by name: must hold module_mutex. */
@@ -756,7 +756,7 @@ void __symbol_put(const char *symbol)
const unsigned long *crc;
preempt_disable();
- if (!__find_symbol(symbol, &owner, &crc, 1))
+ if (IS_ERR_VALUE(__find_symbol(symbol, &owner, &crc, 1)))
BUG();
module_put(owner);
preempt_enable();
@@ -902,7 +902,8 @@ static inline int check_modstruct_versio
const unsigned long *crc;
struct module *owner;
- if (!__find_symbol("struct_module", &owner, &crc, 1))
+ if (IS_ERR_VALUE(__find_symbol("struct_module",
+ &owner, &crc, 1)))
BUG();
return check_version(sechdrs, versindex, "struct_module", mod,
crc);
@@ -955,7 +956,7 @@ static unsigned long resolve_symbol(Elf_
/* use_module can fail due to OOM, or module unloading */
if (!check_version(sechdrs, versindex, name, mod, crc) ||
!use_module(mod, owner))
- ret = 0;
+ ret = -EINVAL;
}
return ret;
}
@@ -1348,14 +1349,16 @@ static int verify_export_symbols(struct
const unsigned long *crc;
for (i = 0; i < mod->num_syms; i++)
- if (__find_symbol(mod->syms[i].name, &owner, &crc, 1)) {
+ if (!IS_ERR_VALUE(__find_symbol(mod->syms[i].name,
+ &owner, &crc, 1))) {
name = mod->syms[i].name;
ret = -ENOEXEC;
goto dup;
}
for (i = 0; i < mod->num_gpl_syms; i++)
- if (__find_symbol(mod->gpl_syms[i].name, &owner, &crc, 1)) {
+ if (!IS_ERR_VALUE(__find_symbol(mod->gpl_syms[i].name,
+ &owner, &crc, 1))) {
name = mod->gpl_syms[i].name;
ret = -ENOEXEC;
goto dup;
@@ -1405,7 +1408,7 @@ static int simplify_symbols(Elf_Shdr *se
strtab + sym[i].st_name, mod);
/* Ok if resolved. */
- if (sym[i].st_value != 0)
+ if (!IS_ERR_VALUE(sym[i].st_value))
break;
/* Ok if weak. */
if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-11-21 21:02 UTC | newest]
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2007-11-21 5:56 Modules: Handle symbols that have a zero value Christoph Lameter
2007-11-21 13:38 ` Mathieu Desnoyers
2007-11-21 21:02 ` Christoph Lameter
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