[PATCH] mm/migrate: Mark unmap_and_move() "noinline" to avoid ICE in gcc 4.7.3

[Kevin Hilman]

Geert Uytterhoeven <geert at linux-m68k.org> writes:

[...]

>> build bisect points to commit 21f992084aeb[3], but that doesn't revert
>> cleanly so I haven't got any further than that yet.
>
> I installed gcc-arm-linux-gnueabi (4:4.7.2-1 from Ubuntu 14.04 LTS) and could
> reproduce the ICE. I came up with the workaround below.

Awesome, thanks!

> Does this work for you?

Yes, that patch works well and fixes the regression. Build results for
all the defconfigs here:

   http://kernelci.org/build/khilman/kernel/v4.0-rc6-8294-g2ef3958cc27e/

and the remaining issues arent' realted to this ICE.

> From 7ebe83316eaf1952e55a76754ce7a5832e461b8c Mon Sep 17 00:00:00 2001
> From: Geert Uytterhoeven <geert+renesas at glider.be>
> Date: Wed, 1 Apr 2015 11:22:51 +0200
> Subject: [PATCH] mm/migrate: Mark unmap_and_move() "noinline" to avoid ICE in
>  gcc 4.7.3
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> With gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-12ubuntu1) :
>
>     mm/migrate.c: In function ‘migrate_pages’:
>     mm/migrate.c:1148:1: internal compiler error: in push_minipool_fix, at config/arm/arm.c:13500
>     Please submit a full bug report,
>     with preprocessed source if appropriate.
>     See <file:///usr/share/doc/gcc-4.7/README.Bugs> for instructions.
>     Preprocessed source stored into /tmp/ccPoM1tr.out file, please attach this to your bugreport.
>     make[1]: *** [mm/migrate.o] Error 1
>     make: *** [mm/migrate.o] Error 2
>
> Mark unmap_and_move() (which is used in a single place only) "noinline"
> to work around this compiler bug.
>
> Reported-by: Kevin Hilman <khilman at kernel.org>
> Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>

Tested-by: Kevin Hilman <khilman at linaro.org>

> ---
>  mm/migrate.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 114602a68111d809..98f8574456c2010c 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -904,9 +904,10 @@ out:
>   * Obtain the lock on page, remove all ptes and migrate the page
>   * to the newly allocated page in newpage.
>   */
> -static int unmap_and_move(new_page_t get_new_page, free_page_t put_new_page,
> -			unsigned long private, struct page *page, int force,
> -			enum migrate_mode mode)
> +static noinline int unmap_and_move(new_page_t get_new_page,
> +				   free_page_t put_new_page,
> +				   unsigned long private, struct page *page,
> +				   int force, enum migrate_mode mode)
>  {
>  	int rc = 0;
>  	int *result = NULL;