From: Dave Hansen <dave@linux.vnet.ibm.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, Ben Blum <bblum@google.com>
Subject: Re: [patch 3/4 -mm] flex_array: poison free elements
Date: Mon, 24 Aug 2009 14:16:58 -0700 [thread overview]
Message-ID: <1251148618.22398.8188.camel@nimitz> (raw)
In-Reply-To: <alpine.DEB.2.00.0908241330361.5574@chino.kir.corp.google.com>
On Mon, 2009-08-24 at 13:41 -0700, David Rientjes wrote:
> LEX_ARRAY_FREE (or an additional poison value to
> distinguish between use-uninitialized vs. use-after-free) must be used in
> flex_array_clear() otherwise the cgroup patchset, the only proposed user
> of this library code, could never shrink this array when pid's are free
> like the kmalloc vs. vmalloc patchset could do.
Are you saying that you expected it to never reallocate the array, but
have a permanent flex_array and that it just calls flex_array_clear() on
the elements that it doesn't want any more, and the array ends up
sparsely populated? I can see why we'd need a poison value in that
case.
Or, are we just talking about a situation where we need to truncate the
pidlist?
-- Dave
next prev parent reply other threads:[~2009-08-24 21:17 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-21 23:21 [patch 1/4 -mm] flex_array: convert element_nr formals to unsigned David Rientjes
2009-08-21 23:21 ` [patch 2/4 -mm] flex_array: add flex_array_clear function David Rientjes
2009-08-24 15:41 ` Dave Hansen
2009-08-24 20:29 ` David Rientjes
2009-08-24 20:38 ` Dave Hansen
2009-08-24 20:50 ` David Rientjes
2009-08-24 21:28 ` Dave Hansen
2009-08-24 22:32 ` David Rientjes
2009-08-21 23:21 ` [patch 3/4 -mm] flex_array: poison free elements David Rientjes
2009-08-24 15:56 ` Dave Hansen
2009-08-24 20:41 ` David Rientjes
2009-08-24 21:16 ` Dave Hansen [this message]
2009-08-24 22:40 ` David Rientjes
2009-08-24 21:42 ` Dave Hansen
2009-08-24 22:44 ` David Rientjes
2009-09-08 22:26 ` David Rientjes
2009-09-09 2:05 ` Li Zefan
2009-09-09 3:18 ` David Rientjes
2009-09-09 3:31 ` Li Zefan
2009-09-09 3:41 ` David Rientjes
2009-09-09 3:45 ` Li Zefan
2009-09-09 4:15 ` David Rientjes
2009-09-09 15:28 ` Dave Hansen
2009-09-09 19:18 ` David Rientjes
2009-09-09 19:22 ` Dave Hansen
2009-09-09 19:34 ` David Rientjes
2009-08-21 23:21 ` [patch 4/4 -mm] flex_array: add flex_array_shrink function David Rientjes
2009-08-21 23:49 ` Andrew Morton
2009-08-22 0:02 ` Randy Dunlap
2009-08-22 21:28 ` David Rientjes
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