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authorRusty Russell <rusty@rustcorp.com.au>2008-01-14 00:55:03 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-01-14 08:52:22 -0800
commitcb2a52052cebe4716e83b9d2e53682ba00f67de6 (patch)
treedf35653a4ef0123c20df72f1c4355562553e9558
parent1a1b285c24e1468afe82b09330dde5192a6e0013 (diff)
downloadlinux-stericsson-cb2a52052cebe4716e83b9d2e53682ba00f67de6.tar.gz
modules: de-mutex more symbol lookup paths in the module code
Kyle McMartin reports sysrq_timer_list_show() can hit the module mutex from hard interrupt context. These paths don't need to though, since we long ago changed all the module list manipulation to occur via stop_machine(). Disabling preemption is enough. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/module.c29
1 files changed, 18 insertions, 11 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 91fe6958b6e1..c2e3e2e98801 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2214,29 +2214,34 @@ static const char *get_ksymbol(struct module *mod,
/* For kallsyms to ask for address resolution. NULL means not found.
We don't lock, as this is used for oops resolution and races are a
lesser concern. */
+/* FIXME: Risky: returns a pointer into a module w/o lock */
const char *module_address_lookup(unsigned long addr,
unsigned long *size,
unsigned long *offset,
char **modname)
{
struct module *mod;
+ const char *ret = NULL;
+ preempt_disable();
list_for_each_entry(mod, &modules, list) {
if (within(addr, mod->module_init, mod->init_size)
|| within(addr, mod->module_core, mod->core_size)) {
if (modname)
*modname = mod->name;
- return get_ksymbol(mod, addr, size, offset);
+ ret = get_ksymbol(mod, addr, size, offset);
+ break;
}
}
- return NULL;
+ preempt_enable();
+ return ret;
}
int lookup_module_symbol_name(unsigned long addr, char *symname)
{
struct module *mod;
- mutex_lock(&module_mutex);
+ preempt_disable();
list_for_each_entry(mod, &modules, list) {
if (within(addr, mod->module_init, mod->init_size) ||
within(addr, mod->module_core, mod->core_size)) {
@@ -2246,12 +2251,12 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
if (!sym)
goto out;
strlcpy(symname, sym, KSYM_NAME_LEN);
- mutex_unlock(&module_mutex);
+ preempt_enable();
return 0;
}
}
out:
- mutex_unlock(&module_mutex);
+ preempt_enable();
return -ERANGE;
}
@@ -2260,7 +2265,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
{
struct module *mod;
- mutex_lock(&module_mutex);
+ preempt_disable();
list_for_each_entry(mod, &modules, list) {
if (within(addr, mod->module_init, mod->init_size) ||
within(addr, mod->module_core, mod->core_size)) {
@@ -2273,12 +2278,12 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
strlcpy(modname, mod->name, MODULE_NAME_LEN);
if (name)
strlcpy(name, sym, KSYM_NAME_LEN);
- mutex_unlock(&module_mutex);
+ preempt_enable();
return 0;
}
}
out:
- mutex_unlock(&module_mutex);
+ preempt_enable();
return -ERANGE;
}
@@ -2287,7 +2292,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
{
struct module *mod;
- mutex_lock(&module_mutex);
+ preempt_disable();
list_for_each_entry(mod, &modules, list) {
if (symnum < mod->num_symtab) {
*value = mod->symtab[symnum].st_value;
@@ -2296,12 +2301,12 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
KSYM_NAME_LEN);
strlcpy(module_name, mod->name, MODULE_NAME_LEN);
*exported = is_exported(name, mod);
- mutex_unlock(&module_mutex);
+ preempt_enable();
return 0;
}
symnum -= mod->num_symtab;
}
- mutex_unlock(&module_mutex);
+ preempt_enable();
return -ERANGE;
}
@@ -2324,6 +2329,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
unsigned long ret = 0;
/* Don't lock: we're in enough trouble already. */
+ preempt_disable();
if ((colon = strchr(name, ':')) != NULL) {
*colon = '\0';
if ((mod = find_module(name)) != NULL)
@@ -2334,6 +2340,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
if ((ret = mod_find_symname(mod, name)) != 0)
break;
}
+ preempt_enable();
return ret;
}
#endif /* CONFIG_KALLSYMS */