Re: linux-next: build failure after merge of the aio tree

From: Stephen Rothwell
Date: Tue Jan 26 2016 - 21:40:30 EST


Hi Benjamin,

On Tue, 12 Jan 2016 11:38:35 -0500 Benjamin LaHaise <bcrl@xxxxxxxxx> wrote:
>
> On Tue, Jan 12, 2016 at 04:40:34PM +1100, Stephen Rothwell wrote:
> >
> > After merging the aio tree, today's linux-next build (arm
> > multi_v7_defconfig) failed like this:
> >
> > fs/built-in.o: In function `aio_thread_op_foo_at':
> > file.c:(.text+0x43808): undefined reference to `__get_user_bad'
> > file.c:(.text+0x43838): undefined reference to `__get_user_bad'
>
> This is very strange. It seems to imply that __get_user() doesn't
> handle 64 bit values, which is completely broken behaviour on the
> architecture's part if true. Can any ARM folks comment on the right
> fix here?

Well, probably only if you cc them :-)

Indeed, __get_user on arm does not handle 64 bit objects, where as
get_user does ...

Background: new aio code is adding __get_user() calls referencing 64
bit quantities (__u64 and __s64).

--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx