Re: Modules: Handle symbols that have a zero value

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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 <[email protected]>
Cc: Kay Sievers <[email protected]
Signed-off-by: Christoph Lameter <[email protected]>

---
 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)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux