[RFC PATCH 1/5] module: Wait for RCU synchronizing before releasing a module

From: Masami Hiramatsu
Date: Mon Aug 25 2014 - 06:55:42 EST

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@xxxxxxxxxxx>
kernel/module.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/module.c b/kernel/module.c
index 03214bd2..4c8a4f1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3324,6 +3324,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
/* Unlink carefully: kallsyms could be walking list. */
+ /* Wait for RCU synchronizing before releasing mod->list. */
+ synchronize_rcu();
module_deallocate(mod, info);

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