Re: [PATCH] mm: Fix section mismatch in memcontrol.c

From: KAMEZAWA Hiroyuki
Date: Wed Jan 14 2009 - 01:50:36 EST


On Wed, 14 Jan 2009 13:14:54 +0800
Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:

> KAMEZAWA Hiroyuki wrote:
> > On Wed, 14 Jan 2009 10:43:24 +0600
> > "Rakib Mullick" <rakib.mullick@xxxxxxxxx> wrote:
> >
> >> Sure. You can carryout your other jobs. Here is the patch.
> >> Thanks for your help guys.
> >>
> > Thank you. I confirmed this fixes mismatch.
> >
> > Could you send this with your Signed-off-by, again ?
> >
> > you got my Ack.
> > Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> >
>
> No... This patch is still not correct..
>
> It's mem_cgroup_create() but not enable_swap_cgroup() that needs
> to be marked as __init_refok.
>
> Here is the correct one:
>
Ah..maybe you're right.

BTW, reading inclinde/linux/init.h again

==
/* modpost check for section mismatches during the kernel build.
* A section mismatch happens when there are references from a
* code or data section to an init section (both code or data).
* The init sections are (for most archs) discarded by the kernel
* when early init has completed so all such references are potential bugs.
* For exit sections the same issue exists.
* The following markers are used for the cases where the reference to
* the *init / *exit section (code or data) is valid and will teach
* modpost not to issue a warning.
* The markers follow same syntax rules as __init / __initdata. */
#define __ref __section(.ref.text) noinline
#define __refdata __section(.ref.data)
#define __refconst __section(.ref.rodata)

==

It seems init_refok is old style.

Could you convert to __ref ?

-Kame



> ===============
>
> From: Li Zefan <lizf@xxxxxxxxxxxxxx>
> Date: Wed, 14 Jan 2009 13:07:31 +0800
> Subject: [PATCH] memcg: fix section mismatch
>
> At system boot when creating the top cgroup, mem_cgroup_create() calls
> enable_swap_cgroup() which is marked as __init, so mark mem_cgroup_create()
> as __init_refok to avoid false section mismatch warning.
>
> Reported-by: Rakib Mullick <rakib.mullick@xxxxxxxxx>
> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
> ---
> mm/memcontrol.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index e2996b8..a2c929f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2181,7 +2181,7 @@ static void __init enable_swap_cgroup(void)
> }
> #endif
>
> -static struct cgroup_subsys_state *
> +static struct cgroup_subsys_state * __init_refok
> mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
> {
> struct mem_cgroup *mem, *parent;
> --
> 1.5.4.rc3
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