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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2014-11-10 09:27:29 +1030
committerRusty Russell <rusty@rustcorp.com.au>2014-11-11 17:07:45 +1030
commit461e34aed0550fee706a9a28fb453830b5079ea0 (patch)
tree6a0a337bc67f6c1347866a7feceebfcf135cfcc2
parent4f48795b6154852d07d971e402c35ecc460ddcb6 (diff)
module: Unlink module with RCU synchronizing instead of stop_machine
Unlink module from module list with RCU synchronizing instead of using stop_machine(). Since module list is already protected by rcu, we don't need stop_machine() anymore. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--kernel/module.c18
1 files changed, 5 insertions, 13 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 331b03f6b411..bed608b8c8a6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1697,18 +1697,6 @@ static void mod_sysfs_teardown(struct module *mod)
mod_sysfs_fini(mod);
}
-/*
- * unlink the module with the whole machine is stopped with interrupts off
- * - this defends against kallsyms not taking locks
- */
-static int __unlink_module(void *_mod)
-{
- struct module *mod = _mod;
- list_del(&mod->list);
- module_bug_cleanup(mod);
- return 0;
-}
-
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
/*
* LKM RO/NX protection: protect module's text/ro-data
@@ -1860,7 +1848,11 @@ static void free_module(struct module *mod)
/* Now we can delete it from the lists */
mutex_lock(&module_mutex);
- stop_machine(__unlink_module, mod, NULL);
+ /* Unlink carefully: kallsyms could be walking list. */
+ list_del_rcu(&mod->list);
+ /* Wait for RCU synchronizing before releasing mod->list. */
+ synchronize_rcu();
+ module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
/* This may be NULL, but that's OK */