netdev - [PATCH][NETNS]: The ip6_fib_timer can work with garbage on net namespace stop.

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Message-ID: <480C912E.70900@openvz.org>
Date:	Mon, 21 Apr 2008 17:05:50 +0400
From:	Pavel Emelyanov <xemul@...nvz.org>
To:	Linux Netdev List <netdev@...r.kernel.org>,
	David Miller <davem@...emloft.net>
Subject: [PATCH][NETNS]: The ip6_fib_timer can work with garbage on net namespace
 stop.

The del_timer() function doesn't guarantee, that the timer callback
is not active by the time it exits.

Thus, the fib6_net_exit() may kfree() all the data, that is required
by the fib6_run_gc(). The race window is tiny, but slab poisoning can
trigger this bug.

Using del_timer_sync() will cure this.

Signed-off-by: Pavel Emelyanov <xemul@...nvz.org>

---

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 50f3f8f..1ee4fa1 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1543,7 +1543,7 @@ out_timer:
 static void fib6_net_exit(struct net *net)
 {
 	rt6_ifdown(net, NULL);
-	del_timer(net->ipv6.ip6_fib_timer);
+	del_timer_sync(net->ipv6.ip6_fib_timer);
 	kfree(net->ipv6.ip6_fib_timer);
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 	kfree(net->ipv6.fib6_local_tbl);
--
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