linux-kernel - Re: [PATCH] cgroup: fix reverse unlock sequence in cgroup_get

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: <6599ad830907210834y30e7d57aj978898a300a447d0@mail.gmail.com>
Date:	Tue, 21 Jul 2009 08:34:51 -0700
From:	Paul Menage <menage@...gle.com>
To:	balbir@...ux.vnet.ibm.com
Cc:	Zefan Li <lizf.kernel@...il.com>, Xiaotian Feng <dfeng@...hat.com>,
	lizf@...fujitsu.com, containers@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cgroup: fix reverse unlock sequence in cgroup_get_sb

On Tue, Jul 21, 2009 at 5:01 AM, Balbir Singh<balbir@...ux.vnet.ibm.com> wrote:
>
> lock(A)
> lock(B)
> unlock(A)
> unlock(B)
>
> Tomorrow if a unsuspecting programmer does this
>
> lock(A)
> lock(B)
> unlock(A)
>
> code block
>
> unlock(B)
>
>
> What protects code block? lock B? Is that the intention?
>

An "unsuspecting programmer" shouldn't be adding code to
multi-threaded routines without thoroughly understanding the locking.

I guess there's no harm in this patch, but as Li says, it doesn't
really change anything.

Paul
--
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/