From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>,
akpm@linux-foundation.org, sergey.senozhatsky.work@gmail.com,
mhocko@kernel.org, kirill.shutemov@linux.intel.com,
sfr@canb.auug.org.au, linux-mm@kvack.org,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
riel@redhat.com, aarcange@redhat.com
Subject: Re: [PATCH] mm, thp: fix locking inconsistency in collapse_huge_page
Date: Thu, 9 Jun 2016 12:51:08 +0900 [thread overview]
Message-ID: <20160609035108.GD655@swordfish> (raw)
In-Reply-To: <12918dcd-a695-c6f4-e06f-69141c5f357f@suse.cz>
On (06/06/16 15:05), Vlastimil Babka wrote:
[..]
> I think this does fix the inconsistency, thanks.
>
> But looking at collapse_huge_page() as of latest -next, I wonder if there's
> another problem:
>
> pmd = mm_find_pmd(mm, address);
> ...
> up_read(&mm->mmap_sem);
> down_write(&mm->mmap_sem);
> hugepage_vma_revalidate(mm, address);
> ...
> pte = pte_offset_map(pmd, address);
>
> What guarantees that 'pmd' is still valid?
the same question applied to __collapse_huge_page_swapin(), I think.
__collapse_huge_page_swapin(pmd)
pte = pte_offset_map(pmd, address);
do_swap_page(mm, vma, _address, pte, pmd...)
up_read(&mm->mmap_sem);
down_read(&mm->mmap_sem);
pte = pte_offset_map(pmd, _address);
-ss
prev parent reply other threads:[~2016-06-09 3:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 3:11 linux-next: Tree for Jun 1 Stephen Rothwell
2016-06-02 1:48 ` [linux-next: Tree for Jun 1] __khugepaged_exit rwsem_down_write_failed lockup Sergey Senozhatsky
2016-06-02 9:21 ` Michal Hocko
2016-06-02 12:08 ` Sergey Senozhatsky
2016-06-02 12:21 ` Michal Hocko
2016-06-03 13:51 ` Andrea Arcangeli
2016-06-03 14:46 ` Michal Hocko
2016-06-03 15:10 ` Andrea Arcangeli
2016-06-07 7:34 ` Michal Hocko
2016-06-08 8:19 ` Vlastimil Babka
2016-06-03 7:15 ` Sergey Senozhatsky
2016-06-03 7:25 ` Michal Hocko
2016-06-03 8:43 ` Sergey Senozhatsky
2016-06-03 9:55 ` Michal Hocko
2016-06-03 10:05 ` Michal Hocko
2016-06-03 13:38 ` Sergey Senozhatsky
2016-06-03 13:45 ` Michal Hocko
2016-06-03 13:49 ` Michal Hocko
2016-06-04 7:51 ` Sergey Senozhatsky
2016-06-06 8:39 ` Michal Hocko
2016-06-02 13:24 ` Vlastimil Babka
2016-06-02 18:58 ` Ebru Akagunduz
2016-06-03 1:00 ` Sergey Senozhatsky
2016-06-03 1:29 ` Sergey Senozhatsky
2016-06-03 4:14 ` Sergey Senozhatsky
2016-06-03 12:28 ` [PATCH] mm, thp: fix locking inconsistency in collapse_huge_page Ebru Akagunduz
2016-06-06 13:05 ` Vlastimil Babka
2016-06-09 3:51 ` Sergey Senozhatsky [this message]
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