linux-kernel - Re: [PATCH 1/2] mm: Remove redundant test from find_get_pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20181123104732.gvhdqyddbsiq3i42@kshutemo-mobl1>
Date:   Fri, 23 Nov 2018 13:47:32 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Hugh Dickins <hughd@...gle.com>
Subject: Re: [PATCH 1/2] mm: Remove redundant test from find_get_pages_contig

On Thu, Nov 22, 2018 at 01:32:23PM -0800, Matthew Wilcox wrote:
> After we establish a reference on the page, we check the pointer continues
> to be in the correct position in i_pages.  There's no need to check the
> page->mapping or page->index afterwards; if those can change after we've
> got the reference, they can change after we return the page to the caller.

Hm. IIRC, page->mapping can be set to NULL due truncation, but what about
index? When it can be changed? Truncation doesn't touch it.

-- 
 Kirill A. Shutemov