From: Paul Menage <menage@google.com>
To: balbir@linux.vnet.ibm.com
Cc: Zefan Li <lizf.kernel@gmail.com>,
Xiaotian Feng <dfeng@redhat.com>,
lizf@cn.fujitsu.com, containers@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cgroup: fix reverse unlock sequence in cgroup_get_sb
Date: Tue, 21 Jul 2009 08:34:51 -0700 [thread overview]
Message-ID: <6599ad830907210834y30e7d57aj978898a300a447d0@mail.gmail.com> (raw)
In-Reply-To: <20090721120106.GW24157@balbir.in.ibm.com>
On Tue, Jul 21, 2009 at 5:01 AM, Balbir Singh<balbir@linux.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
next prev parent reply other threads:[~2009-07-21 15:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-21 10:25 Xiaotian Feng
2009-07-21 11:10 ` Balbir Singh
2009-07-21 11:12 ` Danny Feng
[not found] ` <8522a3d30907210438u6fce081fi835bf964d0c01e8a@mail.gmail.com>
2009-07-21 12:01 ` Balbir Singh
2009-07-21 15:34 ` Paul Menage [this message]
2009-07-21 15:47 ` Balbir Singh
2009-07-22 0:53 ` Li Zefan
2009-07-22 1:42 ` Danny Feng
2009-07-21 16:03 ` Paul Menage
2009-07-22 1:57 ` Danny Feng
2009-07-22 2:18 ` Li Zefan
2009-07-22 2:32 ` Danny Feng
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