linux-kernel - Re: [PATCH] ubifs: Get/put page when changing PG

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: <386368225.TvJUPtmGVW@blindfold>
Date:   Fri, 21 Dec 2018 09:56:25 +0100
From:   Richard Weinberger <richard@....at>
To:     linux-mtd@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        hsiangkao@...l.ru, kirill.shutemov@...ux.intel.com,
        stable@...r.kernel.org, zhangjun <openzhangj@...il.com>
Subject: Re: [PATCH] ubifs: Get/put page when changing PG_private

Am Samstag, 15. Dezember 2018, 16:01:30 CET schrieb Richard Weinberger:
> The page migration code assumes that a page with PG_private
> set has its page count elevated by 1.
> UBIFS never did this and therefore the migration code was unable
> to migrate some pages owned by UBIFS.
> The lead to situations where the CMA memory allocator failed to
> allocate memory.
> 
> Fix this by using get/put_page when changing PG_private.
> 
> Cc: <stable@...r.kernel.org>
> Cc: zhangjun <openzhangj@...il.com>
> Fixes: 4ac1c17b2044 ("UBIFS: Implement ->migratepage()")
> Reported-by: zhangjun <openzhangj@...il.com>
> Signed-off-by: Richard Weinberger <richard@....at>

FYI, on the XFS side a similar change caused a regression.
https://marc.info/?l=linux-fsdevel&m=154530861202448&w=2

Until this regression is not fully understood, including the implications
for UBIFS, I'll not merge this patch.

Thanks,
//richard