From: Krishna Kumar <krkumar2@xxxxxxxxxx>
When using ipv6+netfilter on vlan devices, we were getting
this hang consistantly in an internal distribution:
"unregister_netdevice: waiting for eth0.103 to become free. Usage count = 9"
Sometimes the hang is temporary lasting ~45 secs, and at
other times it is permanent. While fixing the internal bug,
I found the same bug exists in the current kernel.
In ip6_route_me_harder, besides dropping dst, I also moved
the check for dst->error up instead of waiting for the
xfrm_lookup result.
(untested since this bug was not reproducible on my system,
but this patch fixes the hang on the internal distro bits)
Signed-off-by: Krishna Kumar <krkumar2@xxxxxxxxxx>
---
net/ipv6/netfilter.c | 13 +++++++------
net/ipv6/netfilter/ip6t_REJECT.c | 6 ++++--
2 files changed, 11 insertions(+), 8 deletions(-)
diff -ruNp org/net/ipv6/netfilter/ip6t_REJECT.c new/net/ipv6/netfilter/ip6t_REJECT.c
--- org/net/ipv6/netfilter/ip6t_REJECT.c 2010-02-04 14:05:26.000000000 +0530
+++ new/net/ipv6/netfilter/ip6t_REJECT.c 2010-02-04 14:23:23.000000000 +0530
@@ -43,7 +43,7 @@ static void send_reset(struct net *net,
int tcphoff, needs_ack;
const struct ipv6hdr *oip6h = ipv6_hdr(oldskb);
struct ipv6hdr *ip6h;
- struct dst_entry *dst = NULL;
+ struct dst_entry *dst;
u8 proto;
struct flowi fl;
@@ -97,8 +97,10 @@ static void send_reset(struct net *net,
dst = ip6_route_output(net, NULL, &fl);
if (dst == NULL)
return;
- if (dst->error || xfrm_lookup(net, &dst, &fl, NULL, 0))
+ if (dst->error || xfrm_lookup(net, &dst, &fl, NULL, 0)) {
+ dst_release(dst);
return;
+ }
hh_len = (dst->dev->hard_header_len + 15)&~15;
nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr)
diff -ruNp org/net/ipv6/netfilter.c new/net/ipv6/netfilter.c
--- org/net/ipv6/netfilter.c 2010-02-04 14:05:16.000000000 +0530
+++ new/net/ipv6/netfilter.c 2010-02-04 14:07:16.000000000 +0530
@@ -25,6 +25,12 @@ int ip6_route_me_harder(struct sk_buff *
};
dst = ip6_route_output(net, skb->sk, &fl);
+ if (dst->error) {
+ IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
+ LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
+ dst_release(dst);
+ return -EINVAL;
+ }
#ifdef CONFIG_XFRM
if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
@@ -32,6 +38,7 @@ int ip6_route_me_harder(struct sk_buff *
struct dst_entry *dst2 = skb_dst(skb);
if (xfrm_lookup(net, &dst2, &fl, skb->sk, 0)) {
+ dst_release(dst);
skb_dst_set(skb, NULL);
return -1;
}
@@ -39,12 +46,6 @@ int ip6_route_me_harder(struct sk_buff *
}
#endif
- if (dst->error) {
- IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
- LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
- dst_release(dst);
- return -EINVAL;
- }
/* Drop old route. */
skb_dst_drop(skb);
--
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