Re: FAILED: patch "[PATCH] mm/hugetlb: add migration/hwpoisoned entry check in" failed to apply to 3.10-stable tree

Re: FAILED: patch "[PATCH] mm/hugetlb: add migration/hwpoisoned entry check in" failed to apply to 3.10-stable tree

[gregkh]

On Mon, Mar 16, 2015 at 08:36:13AM +0000, Naoya Horiguchi wrote:
> On Wed, Mar 11, 2015 at 02:54:04PM +0100, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 3.10-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> > From a8bda28d87c38c6aa93de28ba5d30cc18e865a11 Mon Sep 17 00:00:00 2001
> > From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> > Date: Wed, 11 Feb 2015 15:25:28 -0800
> > Subject: [PATCH] mm/hugetlb: add migration/hwpoisoned entry check in
> >  hugetlb_change_protection
> 
> The conflict is trivial enough to resolve, so please apply the below one.
> 
> Thanks,
> Naoya Horiguchi
> ---
> >From 5babc2f225937be13d7c040d6d850128bd4f7ebf Mon Sep 17 00:00:00 2001
> From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Date: Mon, 16 Mar 2015 16:04:05 +0900
> Subject: [PATCH] mm/hugetlb: add migration/hwpoisoned entry check in
>  hugetlb_change_protection
> 
> There is a race condition between hugepage migration and
> change_protection(), where hugetlb_change_protection() doesn't care about
> migration entries and wrongly overwrites them.  That causes unexpected
> results like kernel crash.  HWPoison entries also can cause the same
> problem.
> 
> This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this
> function to do proper actions.
> 
> [n-horiguchi@ah.jp.nec.com: resolve conflict to apply to v3.10.71]
> Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: James Hogan <james.hogan@imgtec.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Mel Gorman <mel@csn.ul.ie>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@suse.cz>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Luiz Capitulino <lcapitulino@redhat.com>
> Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
> Cc: Steve Capper <steve.capper@linaro.org>
> Cc: <stable@vger.kernel.org>	[2.6.36+]
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> ---
>  mm/hugetlb.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 7de4f67c81fe..e25e32f5e0e1 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -3116,7 +3116,26 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
>  			pages++;
>  			continue;
>  		}
> -		if (!huge_pte_none(huge_ptep_get(ptep))) {
> +		pte = huge_ptep_get(ptep);
> +		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
> +			spin_unlock(ptl);
> +			continue;
> +		}
> +		if (unlikely(is_hugetlb_entry_migration(pte))) {
> +			swp_entry_t entry = pte_to_swp_entry(pte);
> +
> +			if (is_write_migration_entry(entry)) {
> +				pte_t newpte;
> +
> +				make_migration_entry_read(&entry);
> +				newpte = swp_entry_to_pte(entry);
> +				set_huge_pte_at(mm, address, ptep, newpte);
> +				pages++;
> +			}
> +			spin_unlock(ptl);

Doesn't compile :(