From: Nadav Amit <namit@vmware.com>
To: "mike.kravetz@oracle.com" <mike.kravetz@oracle.com>,
"ebiggers@google.com" <ebiggers@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Dmitry Vyukov <dvyukov@google.com>,
Hugh Dickins <hughd@google.com>, Minchan Kim <minchan@kernel.org>,
"rientjes@google.com" <rientjes@google.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"mm-commits@vger.kernel.org" <mm-commits@vger.kernel.org>,
"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Michal Hocko <mhocko@kernel.org>,
"nyc@holomorphy.com" <nyc@holomorphy.com>
Subject: Re: + mm-madvise-fix-freeing-of-locked-page-with-madv_free.patch added to -mm tree
Date: Fri, 25 Aug 2017 22:02:57 +0000 [thread overview]
Message-ID: <81C11D6F-653D-4B14-A3A6-E6BB6FB5436D@vmware.com> (raw)
In-Reply-To: <20170824060957.GA29811@dhcp22.suse.cz>
Michal Hocko <mhocko@kernel.org> wrote:
> Hmm, I do not see this neither in linux-mm nor LKML. Strange
>
> On Wed 23-08-17 14:41:21, Andrew Morton wrote:
>> From: Eric Biggers <ebiggers@google.com>
>> Subject: mm/madvise.c: fix freeing of locked page with MADV_FREE
>>
>> If madvise(..., MADV_FREE) split a transparent hugepage, it called
>> put_page() before unlock_page(). This was wrong because put_page() can
>> free the page, e.g. if a concurrent madvise(..., MADV_DONTNEED) has
>> removed it from the memory mapping. put_page() then rightfully complained
>> about freeing a locked page.
>>
>> Fix this by moving the unlock_page() before put_page().
Quick grep shows that a similar flow (put_page() followed by an
unlock_page() ) also happens in hugetlbfs_fallocate(). Isn’t it a problem as
well?
next prev parent reply other threads:[~2017-08-25 22:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <599df681.NreP1dR3/HGSfpCe%akpm@linux-foundation.org>
2017-08-24 6:09 ` Michal Hocko
2017-08-24 6:53 ` Michal Hocko
2017-08-25 21:36 ` Andrew Morton
2017-08-25 22:02 ` Nadav Amit [this message]
2017-08-25 22:31 ` Mike Kravetz
2017-08-25 22:51 ` Nadav Amit
2017-08-25 23:41 ` Mike Kravetz
2017-08-26 21:09 ` Eric Biggers
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