From: Vlastimil Babka <vbabka@suse.cz>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>, linux-mm@kvack.org
Cc: akpm@linux-foundation.org
Subject: Re: [PATCH] mm/mempolicy: Remove BUG_ON() checks for VMA inside mpol_misplaced()
Date: Fri, 1 Sep 2017 15:16:12 +0200 [thread overview]
Message-ID: <8896e04b-9db2-53cd-cdb8-58105a94f84a@suse.cz> (raw)
In-Reply-To: <20170901130137.7617-1-khandual@linux.vnet.ibm.com>
On 09/01/2017 03:01 PM, Anshuman Khandual wrote:
> VMA and its address bounds checks are too late in this function.
> They must have been verified earlier in the page fault sequence.
> Hence just remove them.
>
> Suggested-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/mempolicy.c | 5 -----
> 1 file changed, 5 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 618ab12..3509b84 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -2172,17 +2172,12 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
> int polnid = -1;
> int ret = -1;
>
> - BUG_ON(!vma);
> -
> pol = get_vma_policy(vma, addr);
> if (!(pol->flags & MPOL_F_MOF))
> goto out;
>
> switch (pol->mode) {
> case MPOL_INTERLEAVE:
> - BUG_ON(addr >= vma->vm_end);
> - BUG_ON(addr < vma->vm_start);
> -
> pgoff = vma->vm_pgoff;
> pgoff += (addr - vma->vm_start) >> PAGE_SHIFT;
> polnid = offset_il_node(pol, vma, pgoff);
>
--
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prev parent reply other threads:[~2017-09-01 13:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-01 7:02 [PATCH] mm/mempolicy: Move VMA address bound checks inside mpol_misplaced() Anshuman Khandual
2017-09-01 9:05 ` Vlastimil Babka
2017-09-01 12:17 ` Anshuman Khandual
2017-09-01 12:21 ` Anshuman Khandual
2017-09-01 13:01 ` [PATCH] mm/mempolicy: Remove BUG_ON() checks for VMA " Anshuman Khandual
2017-09-01 13:16 ` Vlastimil Babka [this message]
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