Re: [PATCH 3/3] thread_info: include <current.h> for THREAD_INFO_IN_TASK

From	Mark Rutland <mark.rutland@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] thread_info: include <current.h> for THREAD_INFO_IN_TASK
Date	2016-10-24 12:00 +0200
Message-ID	<svKd1-5NX-21@gated-at.bofh.it> (permalink)
References	<su3Wq-53C-35@gated-at.bofh.it> <su3Wq-53C-37@gated-at.bofh.it> <suiLM-6hM-5@gated-at.bofh.it>
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On Thu, Oct 20, 2016 at 12:29:26PM +0200, Heiko Carstens wrote:
> On Wed, Oct 19, 2016 at 07:28:13PM +0100, Mark Rutland wrote:
> > When CONFIG_THREAD_INFO_IN_TASK is selected, the current_thread_info()
> > macro relies on current having been defined prior to its use. However,
> > not all users of current_thread_info() include <asm/current.h>, and thus
> > current is not guaranteed to be defined.
> > 
> > When CONFIG_THREAD_INFO_IN_TASK is not selected, it's possible that
> > get_current() / current are based upon current_thread_info(), and
> > <asm/current.h> includes <asm/thread_info.h>. Thus always including
> > <asm/current.h> would result in circular dependences on some platforms.
> > 
> > To ensure both cases work, this patch includes <asm/current.h>, but only
> > when CONFIG_THREAD_INFO_IN_TASK is selected.
> > 
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Andy Lutomirski <luto@kernel.org>
> > Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> > Cc: Kees Cook <keescook@chromium.org> 
> > ---
> >  include/linux/thread_info.h | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
> > index c75c6ab..ef1f4b0 100644
> > --- a/include/linux/thread_info.h
> > +++ b/include/linux/thread_info.h
> > @@ -12,6 +12,7 @@
> >  #include <linux/restart_block.h>
> >  
> >  #ifdef CONFIG_THREAD_INFO_IN_TASK
> > +#include <asm/current.h>
> >  #define current_thread_info() ((struct thread_info *)current)
> >  #endif
> 
> FWIW:
> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>

Cheers!

Would you be happy to do the same for patch 2?

Once these have a couple more acks I'll drop these on a (hopefully)
stable branch, tagged so that we can both use them as a base.

Thanks,
Mark.

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[PATCH 3/3] thread_info: include <current.h> for THREAD_INFO_IN_TASK Mark Rutland <mark.rutland@arm.com> - 2016-10-19 20:40 +0200
  Re: [PATCH 3/3] thread_info: include <current.h> for  THREAD_INFO_IN_TASK Heiko Carstens <heiko.carstens@de.ibm.com> - 2016-10-20 12:30 +0200
    Re: [PATCH 3/3] thread_info: include <current.h> for  THREAD_INFO_IN_TASK Mark Rutland <mark.rutland@arm.com> - 2016-10-24 12:00 +0200

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