linux-kernel - Re: [PATCH] mm: Fix the pgtable leak

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: <20190213133624.GB9460@kroah.com>
Date:   Wed, 13 Feb 2019 14:36:24 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Minchan Kim <minchan@...nel.org>
Cc:     linux-mm <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
        Johannes Weiner <hannes@...xchg.org>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Hugh Dickins <hughd@...gle.com>,
        Liu Bo <bo.liu@...ux.alibaba.com>, stable@...r.kernel.org
Subject: Re: [PATCH] mm: Fix the pgtable leak

On Wed, Feb 13, 2019 at 08:29:00PM +0900, Minchan Kim wrote:
> [1] was backported to v4.9 stable tree but it introduces pgtable
> memory leak because with fault retrial, preallocated pagetable
> could be leaked in second iteration.
> To fix the problem, this patch backport [2].
> 
> [1] 5cf3e5ff95876, mm, memcg: fix reclaim deadlock with writeback

This is really commit 63f3655f9501 ("mm, memcg: fix reclaim deadlock
with writeback") which was in 4.9.152, 4.14.94, 4.19.16, and 4.20.3 as
well as 5.0-rc2.

> [2] b0b9b3df27d10, mm: stop leaking PageTables

This commit was in 4.10, so I am guessing that this really is just a
backport of that commit?

If so, it's not the full backport, why not take the whole thing?  Why
only cherry-pick one chunk of it?  Why do we not need the other parts?

thanks,

greg k-h