linux-kernel - Re: [PATCH] mm: fix NR_ISOLATED

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 19 Sep 2012 13:04:56 -0400
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Mel Gorman <mgorman@...e.de>,
	Christoph Lameter <cl@...ux.com>
Subject: Re: [PATCH] mm: fix NR_ISOLATED_[ANON|FILE] mismatch

On Wed, Sep 19, 2012 at 3:45 AM, Minchan Kim <minchan@...nel.org> wrote:
> When I looked at zone stat mismatch problem, I found
> migrate_to_node doesn't decrease NR_ISOLATED_[ANON|FILE]
> if check_range fails.
>
> It can make system hang out.
>
> Cc: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> Cc: Mel Gorman <mgorman@...e.de>
> Cc: Christoph Lameter <cl@...ux.com>
> Signed-off-by: Minchan Kim <minchan@...nel.org>
> ---
>  mm/mempolicy.c |   16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 3d64b36..6bf0860 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -953,16 +953,16 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest,
>
>         vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
>                         flags | MPOL_MF_DISCONTIG_OK, &pagelist);
> -       if (IS_ERR(vma))
> -               return PTR_ERR(vma);
> -
> -       if (!list_empty(&pagelist)) {
> +       if (IS_ERR(vma)) {
> +               err = PTR_ERR(vma);
> +               goto out;
> +       }
> +       if (!list_empty(&pagelist))
>                 err = migrate_pages(&pagelist, new_node_page, dest,
>                                                         false, MIGRATE_SYNC);
> -               if (err)
> -                       putback_lru_pages(&pagelist);
> -       }
> -
> +out:
> +       if (err)
> +               putback_lru_pages(&pagelist);

Good catch!
This is a regression since following commit. So, I doubt we need
all or nothing semantics. Can we revert it instead? (and probably
we need more kind comment for preventing an accident)


commit 0def08e3acc2c9c934e4671487029aed52202d42
Author: Vasiliy Kulikov <segooon@...il.com>
Date:   Tue Oct 26 14:21:32 2010 -0700

    mm/mempolicy.c: check return code of check_range
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/