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authorDavid S. Miller <davem@davemloft.net>2011-03-09 19:55:25 -0800
committerDavid S. Miller <davem@davemloft.net>2011-03-09 19:55:25 -0800
commit7343ff31ebf01691ea4515d3126467434b9d22d6 (patch)
tree13c8180b8aeb82363c1e7b576372c23fa2d5f955 /net
parent03a14ab134f4811ab1475f07b1305ccaf38b690f (diff)
downloadlinux-linaro-stable-7343ff31ebf01691ea4515d3126467434b9d22d6.tar.gz
ipv6: Don't create clones of host routes.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=29252 Addresses https://bugzilla.kernel.org/show_bug.cgi?id=30462 In commit d80bc0fd262ef840ed4e82593ad6416fa1ba3fc4 ("ipv6: Always clone offlink routes.") we forced the kernel to always clone offlink routes. The reason we do that is to make sure we never bind an inetpeer to a prefixed route. The logic turned on here has existed in the tree for many years, but was always off due to a protecting CPP define. So perhaps it's no surprise that there is a logic bug here. The problem is that we canot clone a route that is already a host route (ie. has DST_HOST set). Because if we do, an identical entry already exists in the routing tree and therefore the ip6_rt_ins() call is going to fail. This sets off a series of failures and high cpu usage, because when ip6_rt_ins() fails we loop retrying this operation a few times in order to handle a race between two threads trying to clone and insert the same host route at the same time. Fix this by simply using the route as-is when DST_HOST is set. Reported-by: slash@ac.auone-net.jp Reported-by: Ernst Sjöstrand <ernstp@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/route.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 904312e25a3c..e7db7014e89f 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -739,8 +739,10 @@ restart:
if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
nrt = rt6_alloc_cow(rt, &fl->fl6_dst, &fl->fl6_src);
- else
+ else if (!(rt->dst.flags & DST_HOST))
nrt = rt6_alloc_clone(rt, &fl->fl6_dst);
+ else
+ goto out2;
dst_release(&rt->dst);
rt = nrt ? : net->ipv6.ip6_null_entry;