Re: linux-next: Tree for Jan 12 (build failures: m68k, ppc)

From: Guenter Roeck
Date: Thu Jan 15 2015 - 09:09:56 EST


On 01/15/2015 02:12 AM, Geert Uytterhoeven wrote:
On Mon, Jan 12, 2015 at 6:59 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
Build failures, seen since next-20150109:
m68k:allmodconfig
powerpc:ppc6xx_defconfig

It looks like parisc is also suffering:
http://kisskb.ellerman.id.au/kisskb/buildresult/12343847/

Due to:
ERROR: "__get_user_bad" [drivers/gpu/drm/drm.ko] undefined!
make[1]: *** [__modpost] Error 1

Caused by commit d34f20d6e2f (drm: Atomic modeset ioctl).

Yeah, it needs a get_user() that supports 64-bit data.

Hi Geert,

I assume you mean m68k, where 64 bit support for get_user has been disabled.

The problem on powerpc is different though: __get_user_nocheck()
and __get_user_check() use
unsigned long __gu_val;
followed by
__get_user_size(__gu_val, __gu_addr, (size), __gu_err);

__get_user_size() fails in
if (size > sizeof(x))
(x) = __get_user_bad();

Presumably "unsigned long" is 32 bit on 32 bit powerpc, not 64 bit.

Overall, the explicit 64-bit use of get_user() seems to be quite unusual.

I noticed you've sent a fix for DRM.

Doh, and I was just fixing m68k...


Sorry, should have Cc:'d you.

Guenter

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