Commit 4f48795b authored Nov 10, 2014 by Masami Hiramatsu Committed by Rusty Russell Nov 11, 2014

module: Wait for RCU synchronizing before releasing a module



Wait for RCU synchronizing on failure path of module loading
before releasing struct module, because the memory of mod->list
can still be accessed by list walkers (e.g. kallsyms).

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

parent 0df1f248

kernel/module.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -3326,6 +3326,8 @@ static int load_module(struct load_info info, const char __user uargs,
		/* Unlink carefully: kallsyms could be walking list. */
		list_del_rcu(&mod->list);
		wake_up_all(&module_wq);
		/* Wait for RCU synchronizing before releasing mod->list. */
		synchronize_rcu();
		mutex_unlock(&module_mutex);
		free_module:
		module_deallocate(mod, info);