Commit 97a6ec4ac021 ("rhashtable: Change rhashtable_walk_start to
return void") only initialized ret for the first time, when going
to again path, the next tsp could be NULL. Without resetting ret,
cb_done would be called with tsp as NULL.

A kernel crash was caused by this when running sctpdiag testcase
in sctp-tests.

Note that this issue doesn't affect net.git yet.

Fixes: 97a6ec4ac021 ("rhashtable: Change rhashtable_walk_start to return void")
Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/sctp/socket.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 7ff444e..a40fa53 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4860,9 +4860,10 @@ int sctp_for_each_transport(int (*cb)(struct 
sctp_transport *, void *),
                            struct net *net, int *pos, void *p) {
        struct rhashtable_iter hti;
        struct sctp_transport *tsp;
-       int ret = 0;
+       int ret;
 
 again:
+       ret = 0;
        sctp_transport_walk_start(&hti);
 
        tsp = sctp_transport_get_idx(net, &hti, *pos + 1);
-- 
2.1.0

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