From: Mike Kravetz <mike.kravetz@oracle.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Jann Horn <jannh@google.com>,
Youquan Song <youquan.song@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>, Jan Kara <jack@suse.cz>,
John Hubbard <jhubbard@nvidia.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>
Subject: [PATCH 0/2] Fix prep_compound_gigantic_page ref count adjustment
Date: Mon, 21 Jun 2021 19:14:21 -0700 [thread overview]
Message-ID: <20210622021423.154662-1-mike.kravetz@oracle.com> (raw)
These patches address the possible race between prep_compound_gigantic_page
and __page_cache_add_speculative as described by Jann Horn in [1].
The first patch simply removes the unnecessary/obsolete helper routine
prep_compound_huge_page to make the actual fix a little simpler.
The second patch is the actual fix and has a detailed explanation in the
commit message.
This potential issue has existed for almost 10 years and I am unaware of
anyone actually hitting the race. I did not cc stable, but would be
happy to squash the patches and send to stable if anyone thinks that is
a good idea.
I could not think of a reliable way to recreate the issue for testing.
Rather, I 'simulated errors' to exercise all the error paths.
Mike Kravetz (2):
hugetlb: remove prep_compound_huge_page cleanup
hugetlb: address ref count racing in prep_compound_gigantic_page
mm/hugetlb.c | 99 ++++++++++++++++++++++++++++++++++++-------------
mm/page_alloc.c | 1 -
2 files changed, 73 insertions(+), 27 deletions(-)
--
2.31.1
next reply other threads:[~2021-06-22 2:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-22 2:14 Mike Kravetz [this message]
2021-06-22 2:14 ` [PATCH 1/2] hugetlb: remove prep_compound_huge_page cleanup Mike Kravetz
2021-06-22 9:09 ` [External] " Muchun Song
2021-06-22 2:14 ` [PATCH 2/2] hugetlb: address ref count racing in prep_compound_gigantic_page Mike Kravetz
2021-06-23 8:00 ` [External] " Muchun Song
2021-06-24 0:26 ` Mike Kravetz
2021-06-24 3:38 ` Muchun Song
2021-06-22 2:16 ` [PATCH 0/2] Fix prep_compound_gigantic_page ref count adjustment Mike Kravetz
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=20210622021423.154662-1-mike.kravetz@oracle.com \
--to=mike.kravetz@oracle.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=jack@suse.cz \
--cc=jannh@google.com \
--cc=jhubbard@nvidia.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=willy@infradead.org \
--cc=youquan.song@intel.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).