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Subject[PATCH] module: make symbol_put_addr() work for all exported symbols
symbol_put_addr() works only for exported function names (symbols present 
in text section). This for example means that

symbol_put_addr(__symbol_get("any_exported_variable_name"))

triggers a BUG, which really seems wrong.

This patch introduces generic lookup_symbol_address(), which performs
lookup on symbol tables of all modules according to the address, and makes
symbol_put_addr() use this interface to find the module owner instead.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/kernel/module.c b/kernel/module.c
index 5f80478..77ff23e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -302,6 +302,64 @@ static unsigned long find_symbol(const char *name,
return -ENOENT;
}

+/* Lookup module symbol by address */
+const static struct kernel_symbol *lookup_symbol_address(unsigned long addr,
+ struct module **owner)
+{
+ struct module *mod;
+ const struct kernel_symbol *s;
+ unsigned int i;
+
+ /* Core kernel first */
+ struct {
+ const struct kernel_symbol *s_start;
+ const struct kernel_symbol *s_end;
+ } kern_syms[] = {
+ { __start___ksymtab, __stop___ksymtab },
+ { __start___ksymtab_gpl, __stop___ksymtab_gpl },
+ { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future },
+ { __start___ksymtab_unused, __stop___ksymtab_unused },
+ { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl },
+ };
+
+ for (i = 0; i < ARRAY_SIZE(kern_syms); i++) {
+ for (s = kern_syms[i].s_start; s < kern_syms[i].s_end; s++) {
+ if (s->value == addr) {
+ if (owner)
+ *owner = NULL;
+ return s;
+ }
+ }
+ }
+
+ /* Now try modules */
+ list_for_each_entry(mod, &modules, list) {
+ struct {
+ const struct kernel_symbol *sym;
+ unsigned int num;
+ } arr[] = {
+ { mod->syms, mod->num_syms },
+ { mod->gpl_syms, mod->num_gpl_syms },
+ { mod->gpl_future_syms, mod->num_gpl_future_syms },
+ { mod->unused_syms, mod->num_unused_syms },
+ { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
+ };
+
+ for (i = 0; i < ARRAY_SIZE(arr); i++) {
+ for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
+ if (s->value == addr) {
+ if (owner)
+ *owner = mod;
+ return s;
+ }
+ }
+ }
+ }
+ return NULL;
+}
+
+
+
/* Search for module by name: must hold module_mutex. */
static struct module *find_module(const char *name)
{
@@ -799,13 +857,12 @@ EXPORT_SYMBOL(__symbol_put);
void symbol_put_addr(void *addr)
{
struct module *modaddr;
-
- if (core_kernel_text((unsigned long)addr))
- return;
-
- if (!(modaddr = module_text_address((unsigned long)addr)))
+
+ if (!lookup_symbol_address((unsigned long)addr, &modaddr))
BUG();
- module_put(modaddr);
+
+ if(modaddr)
+ module_put(modaddr);
}
EXPORT_SYMBOL_GPL(symbol_put_addr);




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