From: Patrick McHardy <kaber@trash.net>
Date: Wed, 3 Feb 2010 12:24:54 +0000 (+0100)
Subject: netfilter: xt_hashlimit: fix race condition and simplify locking
X-Git-Tag: v2.6.34-rc1~233^2~303^2~36
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2eff25c18c3d332d3c4dd98f2ac9b7114e9771b0;p=pandora-kernel.git

netfilter: xt_hashlimit: fix race condition and simplify locking

As noticed by Shin Hong <hongshin@gmail.com>, there is a race between
htable_find_get() and htable_put():

htable_put():				htable_find_get():

					spin_lock_bh(&hashlimit_lock);
					<search entry>
atomic_dec_and_test(&hinfo->use)
					atomic_inc(&hinfo->use)
					spin_unlock_bh(&hashlimit_lock)
					return hinfo;
spin_lock_bh(&hashlimit_lock);
hlist_del(&hinfo->node);
spin_unlock_bh(&hashlimit_lock);
htable_destroy(hinfo);

The entire locking concept is overly complicated, tables are only
created/referenced and released in process context, so a single
mutex works just fine. Remove the hashinfo_spinlock and atomic
reference count and use the mutex to protect table lookups/creation
and reference count changes.

Signed-off-by: Patrick McHardy <kaber@trash.net>
---

Reading git-diff-tree failed