From: Patrick McHardy <kaber@trash•net>
To: Alexey Dobriyan <adobriyan@gmail•com>
Cc: davem@davemloft•net, jonathan@jonmasters•org,
eric.dumazet@gmail•com, netdev@vger•kernel.org,
netfilter-devel@vger•kernel.org
Subject: Re: [PATCH for 2.6.33] conntrack: restrict runtime hashsize modifications
Date: Thu, 04 Feb 2010 17:18:50 +0100 [thread overview]
Message-ID: <4B6AF36A.3050402@trash.net> (raw)
In-Reply-To: <20100203203929.GA6168@x200>
Alexey Dobriyan wrote:
> Jon Masters correctly points out that conntrack hash sizes
> (nf_conntrack_htable_size) are global (not per-netns) and
> modifiable at runtime via /sys/module/nf_conntrack/hashsize .
>
> Steps to reproduce:
> clone(CLONE_NEWNET)
> [grow /sys/module/nf_conntrack/hashsize]
> exit()
>
> At netns exit we are going to scan random memory for conntracks to be killed.
>
> Apparently there is a code which deals with hashtable resize for
> init_net (and it was there befode netns conntrack code), so prohibit
> hashsize modification if there is more than one netns exists.
>
> To change hashtable sizes, you need to reload module.
>
> Expectation hashtable size was simply glued to a variable with no code
> to rehash expectations, so it was a bug to allow writing to it.
> Make "expect_hashsize" readonly.
>
> This is temporarily until we figure out what to do.
How about alternatively moving nf_conntrack_hsize into the
per-namespace struct? It doesn't look more complicated or
intrusive and would allow to still change the init_net
hashsize. Also seems less hackish :)
next prev parent reply other threads:[~2010-02-04 16:18 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-03 20:39 [PATCH for 2.6.33] conntrack: restrict runtime hashsize modifications Alexey Dobriyan
2010-02-03 20:50 ` Jon Masters
2010-02-04 16:18 ` Patrick McHardy [this message]
2010-02-04 16:27 ` Patrick McHardy
2010-02-04 20:18 ` Jon Masters
2010-02-05 10:00 ` Patrick McHardy
2010-02-05 10:14 ` Jon Masters
2010-02-05 10:21 ` Patrick McHardy
2010-02-04 17:04 ` Patrick McHardy
2010-02-04 19:47 ` Alexey Dobriyan
2010-02-04 20:23 ` Jon Masters
2010-02-05 10:00 ` Patrick McHardy
2010-02-05 10:11 ` Jon Masters
2010-02-05 10:19 ` Patrick McHardy
2010-02-05 11:16 ` Patrick McHardy
2010-02-05 11:19 ` Alexey Dobriyan
2010-02-05 11:22 ` Patrick McHardy
2010-02-05 11:25 ` Patrick McHardy
2010-02-05 11:51 ` Jon Masters
2010-02-05 11:23 ` Alexey Dobriyan
2010-02-05 22:04 ` Alexey Dobriyan
2010-02-08 13:34 ` Patrick McHardy
2010-02-08 14:35 ` Patrick McHardy
2010-02-04 20:20 ` Jon Masters
2010-02-05 10:03 ` Patrick McHardy
2010-02-05 10:12 ` Jon Masters
2010-02-05 10:21 ` Patrick McHardy
2010-02-04 17:26 ` Patrick McHardy
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