[PATCH 4.2 06/30] net/ipv6: Correct PIM6 mrt_lock handling

From: Greg Kroah-Hartman
Date: Thu Oct 01 2015 - 05:27:54 EST


4.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: Richard Laing <richard.laing@xxxxxxxxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxxxxxxxx>
Acked-by: Cong Wang <cwang@xxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6mr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -550,7 +550,7 @@ static void ipmr_mfc_seq_stop(struct seq

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);
}



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