Re: [PATCH 3.12 100/170] hugetlb: fix copy_hugetlb_page_range() to handle migration/hwpoisoned entry

Jiri Slaby
2014-07-20T19:51:31Z

On 07/18/2014 08:53 PM, Hugh Dickins wrote:
> On Fri, 18 Jul 2014, Jiri Slaby wrote:
>
>> From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
>>
>> 3.12-stable review patch. If anyone has any objections, please let me know.
>>
>> ===============
>>
>> commit 4a705fef986231a3e7a6b1a6d3c37025f021f49f upstream.
>>
>> There's a race between fork() and hugepage migration, as a result we try
>> to "dereference" a swap entry as a normal pte, causing kernel panic.
>> The cause of the problem is that copy_hugetlb_page_range() can't handle
>> "swap entry" family (migration entry and hwpoisoned entry) so let's fix
>> it.
>>
>> [akpm@linux-foundation.org: coding-style fixes]
>> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
>> Acked-by: Hugh Dickins <hughd@google.com>
>> Cc: Christoph Lameter <cl@linux.com>
>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
>> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
>
> Please drop this one for now: other -stables have carried it, but it
> was found yesterday to contain a bug of its own, arguably worse than
> what it's fixing. Naoya-san has done the fix for that, it's in mmotm
> and should make its way to Linus probably next week: so please hold
> this back until that can join it - thanks.

Thanks, I dropped it later on Fri already after Guillaume informed me
about this.

--
js
suse labs