net/ipv6: Correct PIM6 mrt_lock handling

[ Upstream commit 25b4a44c19c83d98e8c0807a7ede07c1f28eab8b ]

In the IPv6 multicast routing code the mrt_lock was not being released
correctly in the MFC iterator, as a result adding or deleting a MIF would
cause a hang because the mrt_lock could not be acquired.

This fix is a copy of the code for the IPv4 case and ensures that the lock
is released correctly.

Signed-off-by: Richard Laing <richard.laing@alliedtelesis.co.nz>
Acked-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index f96c96f..99ee86d 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -550,7 +550,7 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
 
        if (it->cache == &mrt->mfc6_unres_queue)
                spin_unlock_bh(&mfc_unres_lock);
-       else if (it->cache == mrt->mfc6_cache_array)
+       else if (it->cache == &mrt->mfc6_cache_array[it->ct])
                read_unlock(&mrt_lock);
 }