linux-kernel - Re: memcmp in modules

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Date:	Fri, 12 Apr 2013 18:08:41 +0300
From:	Andy Shevchenko <andy.shevchenko@...il.com>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: memcmp in modules

HI.

I have an issue with memcmp, but it seems I didn't get what is
happening there. Let's consider the details.

I have a module which has one call of memcmp and licensed as Dual BSD/GPL.

#include <linux/string.h>
...
if (memcmp(...))
...
MODULE_LICENSE("Dual BSD/GPL");

I compile it for ARCH=i386 together with kernel and try to load it.

modprobe test-string_helpers

[   25.134433] test_string_helpers: no symbol version for memcmp
[   25.140156] test_string_helpers: Unknown symbol memcmp (err -22)

Then I've changed string_32.h a bit (I think it's not a solution of the issue)

-#define memcmp __builtin_memcmp
+#define memcmp(a, b, n) __builtin_memcmp(a, b, n)

And in this case:
modprobe test_string_helpers
[   15.391589] test_string_helpers: Running tests...

What did I miss?

--
With Best Regards,
Andy Shevchenko
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