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authorTim Abbott <tabbott@MIT.EDU>2009-01-05 09:40:10 -0500
committerRusty Russell <rusty@rustcorp.com.au>2009-01-04 17:10:11 -0500
commitca4787b779dd698a2a33a328aa5fa90a3e954077 (patch)
tree678eddc5cfd0b366b1ef5662cf6ccdd7b7b2f135 /kernel/module.c
parenta327ca2c2674c5a9a0073421df19bfc362698136 (diff)
kernel/module.c: compare symbol values when marking symbols as exported in /proc/kallsyms.
When there are two symbols in a module with the same name, one of which is exported, both will be marked as exported in /proc/kallsyms. There aren't any instances of this in the current kernel, but it is easy to construct a simple module with two compilation units that exhibits the problem. $ objdump -j .text -t testmod.ko | grep foo 00000000 l F .text 00000032 foo 00000080 g F .text 00000001 foo $ sudo insmod testmod.ko $ grep "T foo" /proc/kallsyms c28e8000 T foo [testmod] c28e8080 T foo [testmod] Fix this by comparing the symbol values once we've found the exported symbol table entry matching the symbol name. Tested using Ksplice: $ ksplice-create --patch=this_commit.patch --id=bar . $ sudo ksplice-apply ksplice-bar.tar.gz Done! $ grep "T foo" /proc/kallsyms c28e8080 T foo [testmod] Signed-off-by: Tim Abbott <tabbott@mit.edu> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/kernel/module.c b/kernel/module.c
index dd2a54155b54..895c5675edb7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1725,15 +1725,15 @@ static const struct kernel_symbol *lookup_symbol(const char *name,
1725 return NULL; 1725 return NULL;
1726} 1726}
1727 1727
1728static int is_exported(const char *name, const struct module *mod) 1728static int is_exported(const char *name, unsigned long value,
1729 const struct module *mod)
1729{ 1730{
1730 if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab)) 1731 const struct kernel_symbol *ks;
1731 return 1; 1732 if (!mod)
1733 ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
1732 else 1734 else
1733 if (mod && lookup_symbol(name, mod->syms, mod->syms + mod->num_syms)) 1735 ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
1734 return 1; 1736 return ks != NULL && ks->value == value;
1735 else
1736 return 0;
1737} 1737}
1738 1738
1739/* As per nm */ 1739/* As per nm */
@@ -2504,7 +2504,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
2504 strlcpy(name, mod->strtab + mod->symtab[symnum].st_name, 2504 strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
2505 KSYM_NAME_LEN); 2505 KSYM_NAME_LEN);
2506 strlcpy(module_name, mod->name, MODULE_NAME_LEN); 2506 strlcpy(module_name, mod->name, MODULE_NAME_LEN);
2507 *exported = is_exported(name, mod); 2507 *exported = is_exported(name, *value, mod);
2508 preempt_enable(); 2508 preempt_enable();
2509 return 0; 2509 return 0;
2510 } 2510 }