linux-kernel - Re: [PATCH 1/2] Revert "Revert "math64: New div64_u64

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: <CAOMFOmXhoBoFrkr8bgP5qV-jZXA=6ZfXnSsg1j5fEVv_RgRAyw@mail.gmail.com>
Date:	Wed, 4 Sep 2013 09:11:25 -0700
From:	Anatol Pomozov <anatol.pomozov@...il.com>
To:	Mike Snitzer <snitzer@...hat.com>
Cc:	dm-devel@...hat.com, LKML <linux-kernel@...r.kernel.org>,
	Mikulas Patocka <mpatocka@...hat.com>,
	Stanislaw Gruszka <sgruszka@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH 1/2] Revert "Revert "math64: New div64_u64_rem helper""

Hi,

On Fri, Aug 9, 2013 at 12:56 PM, Mike Snitzer <snitzer@...hat.com> wrote:
> This reverts commit f3002134158092178be81339ec5a22ff80e6c308.
>
> div64_u64_rem was removed because there were no other users.

In the light of this discussion https://lkml.org/lkml/2013/8/30/417 we
will have more users of div64_u64_rem

For example code from ext4_mb_find_by_goal() function uses function
do_div() with divisor sbi->s_stripe that has "unsigned long" type.
do_div() silently truncates the type to 32bits and do_div() returns
incorrect result (or crash if lower 32bits are zero). It should be
either replaced with div64_u64_rem() posted here or with just "a % b".
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/