From: Song Liu <song@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>, Song Liu <songliubraving@fb.com>,
Jiri Olsa <jolsa@kernel.org>,
David Stevens <stevensd@chromium.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Peter Xu <peterx@redhat.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Yang Shi <shy828301@gmail.com>,
David Hildenbrand <david@redhat.com>,
Jiaqi Yan <jiaqiyan@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 3/3] mm/khugepaged: maintain page cache uptodate flag
Date: Thu, 23 Mar 2023 15:28:22 -0700 [thread overview]
Message-ID: <CAPhsuW5pTh2+S7VjRbRy=WUAb7-GLQpi6HKCW0ehxs5HAup_dQ@mail.gmail.com> (raw)
In-Reply-To: <ZBzK99dSmbPB7vjA@casper.infradead.org>
On Thu, Mar 23, 2023 at 2:56 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Mar 23, 2023 at 12:07:46PM -0700, Hugh Dickins wrote:
> > On an earlier audit, for different reasons, I did also run across
> > lib/buildid.c build_id_parse() using find_get_page() without checking
> > PageUptodate() - looks as if it might do the wrong thing if it races
> > with khugepaged collapsing text to huge, and should probably have a
> > similar fix.
>
> That shouldn't be using find_get_page(). It should probably use
> read_cache_folio() which will actually read in the data if it's not
> present in the page cache, and return an ERR_PTR if the data couldn't
> be read.
build_id_parse() can be called from NMI, so I don't think we can let
read_cache_folio() read-in the data.
Thanks,
Song
next prev parent reply other threads:[~2023-03-23 22:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-07 5:20 [PATCH v5 0/3] mm/khugepaged: fix khugepaged+shmem races David Stevens
2023-03-07 5:20 ` [PATCH v5 1/3] mm/khugepaged: refactor collapse_file control flow David Stevens
2023-03-23 19:51 ` Hugh Dickins
2023-03-07 5:20 ` [PATCH v5 2/3] mm/khugepaged: skip shmem with userfaultfd David Stevens
2023-03-23 19:48 ` Hugh Dickins
2023-03-24 5:34 ` David Stevens
2023-03-28 15:48 ` Peter Xu
2023-03-07 5:20 ` [PATCH v5 3/3] mm/khugepaged: maintain page cache uptodate flag David Stevens
2023-03-23 19:07 ` Hugh Dickins
2023-03-23 21:56 ` Matthew Wilcox
2023-03-23 22:28 ` Song Liu [this message]
2023-03-24 1:56 ` Hugh Dickins
2023-03-24 3:30 ` Matthew Wilcox
2023-03-24 6:03 ` Song Liu
2023-03-24 13:31 ` Matthew Wilcox
2023-03-29 16:53 ` Song Liu
2023-03-28 9:48 ` David Stevens
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