Re: + drivers-acpi-apei-erst-dbgc-get_useru64-doesnt-work-on-i386.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 11 Aug 2010 16:43:10 -0700 Randy Dunlap <randy.dunlap@oracle.com> wrote:

> On Wed, 11 Aug 2010 16:06:24 -0700 akpm@linux-foundation.org wrote:
> 
> > 
> > The patch titled
> >      drivers/acpi/apei/erst-dbg.c: get_user(u64) doesn't work on i386
> > has been added to the -mm tree.  Its filename is
> >      drivers-acpi-apei-erst-dbgc-get_useru64-doesnt-work-on-i386.patch
> > 
> > Before you just go and hit "reply", please:
> >    a) Consider who else should be cc'ed
> >    b) Prefer to cc a suitable mailing list as well
> >    c) Ideally: find the original patch on the mailing list and do a
> >       reply-to-all to that, adding suitable additional cc's
> > 
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> > 
> > See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
> > out what to do about this
> > 
> > The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
> > 
> > ------------------------------------------------------
> > Subject: drivers/acpi/apei/erst-dbg.c: get_user(u64) doesn't work on i386
> > From: Andrew Morton <akpm@linux-foundation.org>
> > 
> > Might be an x86 bug?  A get_user() on a u64 on i386 expands to
> > 
> > #define __get_user_8(__ret_gu, __val_gu, ptr)				\
> > 		__get_user_x(X, __ret_gu, __val_gu, ptr)
> > 
> > which emits a call to __get_user_X(), which doesn't exist.
> > 
> > Kludge around it with copy_from_user().
> > 
> 
> Reported and fixed yesterday.

Not very well.

+		rc = copy_from_user(&record_id, (void __user *)arg,
+				    sizeof(u64));

better to use sizeof(record_id).

Where's Len??


Anyway, this should be fixed in x86 core, I suspect.