linux-kernel - UBIFS and page migration (take 2)

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-next>] [day] [month] [year] [list]

Date:	Thu, 31 Mar 2016 23:58:31 +0200
From:	Richard Weinberger <richard@....at>
To:	linux-fsdevel@...r.kernel.org
Cc:	linux-mtd@...ts.infradead.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, boris.brezillon@...e-electrons.com,
	maxime.ripard@...e-electrons.com, david@...ma-star.at,
	david@...morbit.com, dedekind1@...il.com, alex@...tthing.co,
	akpm@...ux-foundation.org, sasha.levin@...cle.com,
	iamjoonsoo.kim@....com, rvaswani@...eaurora.org,
	tony.luck@...el.com, shailendra.capricorn@...il.com,
	kirill.shutemov@...ux.intel.com, hch@...radead.org,
	hughd@...gle.com, mgorman@...hsingularity.net, vbabka@...e.cz
Subject: UBIFS and page migration (take 2)

During page migrations UBIFS gets confused. We triggered this by using CMA
on two different targets.
It turned out that fallback_migrate_page() is not suitable for UBIFS as it
does not copy the PagePrivate flag.
UBIFS is using this flag among with PageChecked to account free space.
One possible solution is implementing a ->migratepage() function in UBIFS
which does more or less the same as fallback_migrate_page() but also
copies PagePrivate. I'm not at all sure whether this is they way to go.
IMHO either page migration should not happen if ->migratepage() is not implement
or fallback_migrate_page() has to work for all filesystems.

Comments? Flames? :-)

Thanks,
//richard

[PATCH 1/2] mm: Export migrate_page_move_mapping and
[PATCH 2/2] UBIFS: Implement ->migratepage()