From: Miaohe Lin <linmiaohe@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
<n-horiguchi@ah.jp.nec.com>, <hillf.zj@alibaba-inc.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: Re: [PATCH 4/4] mm/hugeltb: handle the error case in hugetlb_fix_reserve_counts()
Date: Fri, 9 Apr 2021 15:07:00 +0800 [thread overview]
Message-ID: <bc24856e-78ca-b44a-bf33-4b540720f72a@huawei.com> (raw)
In-Reply-To: <20210408220453.f95942bf20baadd8dbbc1488@linux-foundation.org>
On 2021/4/9 13:04, Andrew Morton wrote:
> On Fri, 9 Apr 2021 11:17:49 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:
>
>> On 2021/4/9 7:25, Mike Kravetz wrote:
>>> On 4/2/21 2:32 AM, Miaohe Lin wrote:
>>>> A rare out of memory error would prevent removal of the reserve map region
>>>> for a page. hugetlb_fix_reserve_counts() handles this rare case to avoid
>>>> dangling with incorrect counts. Unfortunately, hugepage_subpool_get_pages
>>>> and hugetlb_acct_memory could possibly fail too. We should correctly handle
>>>> these cases.
>>>
>>> Yes, this is a potential issue.
>>>
>>> The 'good news' is that hugetlb_fix_reserve_counts() is unlikely to ever
>>> be called. To do so would imply we could not allocate a region entry
>>> which is only 6 words in size. We also keep a 'cache' of entries so we
>>> may not even need to allocate.
>>>
>>> But, as mentioned it is a potential issue.
>>
>> Yes, a potential *theoretical* issue.
>>
>>>
>>>> Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages")
>>>
>>> This is likely going to make this get picked by by stable releases.
>>> That is unfortunate as mentioned above this is mostly theoretical.
>>>
>>
>> I will drop this. This does not worth backport.
>>
>
> -stable have been asked not to backport MM patches unless MM patches
> include "cc:stable". ie, no making our backporting decisions for us,
> please.
>
Sorry about it! I would retain the Fixes tag.
Many thanks for pointing this out.
> .
>
prev parent reply other threads:[~2021-04-09 7:07 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 9:32 [PATCH 0/4] Cleanup and fixup for hugetlb Miaohe Lin
2021-04-02 9:32 ` [PATCH 1/4] mm/hugeltb: remove redundant VM_BUG_ON() in region_add() Miaohe Lin
2021-04-07 0:16 ` Mike Kravetz
2021-04-02 9:32 ` [PATCH 2/4] mm/hugeltb: simplify the return code of __vma_reservation_common() Miaohe Lin
2021-04-07 0:53 ` Mike Kravetz
2021-04-07 2:05 ` Miaohe Lin
2021-04-07 2:37 ` Mike Kravetz
2021-04-07 3:09 ` Miaohe Lin
2021-04-07 21:23 ` Mike Kravetz
2021-04-08 2:44 ` Miaohe Lin
2021-04-08 22:40 ` Mike Kravetz
2021-04-09 2:52 ` Miaohe Lin
2021-04-02 9:32 ` [PATCH 3/4] mm/hugeltb: fix potential wrong gbl_reserve value for hugetlb_acct_memory() Miaohe Lin
2021-04-07 2:49 ` Mike Kravetz
2021-04-07 7:24 ` Miaohe Lin
2021-04-07 20:53 ` Mike Kravetz
2021-04-08 3:24 ` Miaohe Lin
2021-04-08 3:26 ` Miaohe Lin
2021-04-08 22:53 ` Mike Kravetz
2021-04-09 3:01 ` Miaohe Lin
2021-04-09 4:37 ` Mike Kravetz
2021-04-09 6:36 ` Miaohe Lin
2021-04-02 9:32 ` [PATCH 4/4] mm/hugeltb: handle the error case in hugetlb_fix_reserve_counts() Miaohe Lin
2021-04-08 23:25 ` Mike Kravetz
2021-04-09 3:17 ` Miaohe Lin
2021-04-09 5:04 ` Andrew Morton
2021-04-09 7:07 ` Miaohe Lin [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bc24856e-78ca-b44a-bf33-4b540720f72a@huawei.com \
--to=linmiaohe@huawei.com \
--cc=akpm@linux-foundation.org \
--cc=hillf.zj@alibaba-inc.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mike.kravetz@oracle.com \
--cc=n-horiguchi@ah.jp.nec.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).