xfrm: policy: fix infinite loop when merging src-nodes

With very small change to test script we can trigger softlockup due to
bogus assignment of 'p' (policy to be examined) on restart.

Previously the two to-be-merged nodes had same address/prefixlength pair,
so no erase/reinsert was necessary, we only had to append the list from
node a to b.

If prefix lengths are different, the node has to be deleted and re-inserted
into the tree, with the updated prefix length.  This was broken; due to
bogus update to 'p' this loops forever.

Add a 'restart' label and use that instead.

While at it, don't perform the unneeded reinserts of the policies that
are already sorted into the 'new' node.

A previous patch in this series made xfrm_policy_inexact_list_reinsert()
use the relative position indicator to sort policies according to age in
case priorities are identical.

Fixes: 6ac098b2a9d30 ("xfrm: policy: add 2nd-level saddr trees for inexact policies")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/testing/selftests/net/xfrm_policy.sh b/tools/testing/selftests/net/xfrm_policy.sh
index 8ce54600d4d1..71d7fdc513c1 100755
--- a/tools/testing/selftests/net/xfrm_policy.sh
+++ b/tools/testing/selftests/net/xfrm_policy.sh
@@ -78,8 +78,8 @@ do_overlap()
     # adds a new node in the 10.0.0.0/24 tree (dst node exists).
     ip -net $ns xfrm policy add src 10.2.0.0/24 dst 10.0.0.0/24 dir fwd priority 200 action block
 
-    # adds a 10.2.0.0/24 node, but for different dst.
-    ip -net $ns xfrm policy add src 10.2.0.0/24 dst 10.0.1.0/24 dir fwd priority 200 action block
+    # adds a 10.2.0.0/23 node, but for different dst.
+    ip -net $ns xfrm policy add src 10.2.0.0/23 dst 10.0.1.0/24 dir fwd priority 200 action block
 
     # dst now overlaps with the 10.0.1.0/24 ESP policy in fwd.
     # kernel must 'promote' existing one (10.0.0.0/24) to 10.0.0.0/23.