module: remove over-zealous check in __module_get()

commit 7f9a50a5b89b87f8e754f59ae9968da28be618a5 upstream.

Impact: fix spurious BUG_ON() triggered under load

module_refcount() isn't reliable outside stop_machine(), as demonstrated
by Karsten Keil <kkeil@suse.de>, networking can trigger it under load
(an inc on one cpu and dec on another while module_refcount() is tallying
 can give false results, for example).

Almost noone should be using __module_get, but that's another issue.

Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/module.h b/include/linux/module.h
index 3bfed013350b0e6bac488e7a91e77153926e37d8..446263ca07f7c16ed77b7209f5f3dccb0b86c650 100644 (file)
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -391,7 +391,6 @@ void symbol_put_addr(void *addr);
 static inline void __module_get(struct module *module)
 {
        if (module) {
-               BUG_ON(module_refcount(module) == 0);
                local_inc(&module->ref[get_cpu()].count);
                put_cpu();
        }