[ 30/47] ipv4: Do not use dead fib_info entries.

Greg KH
2012-06-07T04:24:53Z

From: "David S. Miller" <davem@davemloft.net>

[ Upstream commit dccd9ecc374462e5d6a5b8f8110415a86c2213d8 ]

Due to RCU lookups and RCU based release, fib_info objects can
be found during lookup which have fi->fib_dead set.

We must ignore these entries, otherwise we risk dereferencing
the parts of the entry which are being torn down.

Reported-by: Yevgen Pronenko <yevgen.pronenko@sonymobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/fib_trie.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1371,6 +1371,8 @@ static int check_leaf(struct fib_table *

if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
continue;
+ if (fi->fib_dead)
+ continue;
if (fa->fa_info->fib_scope < flp->flowi4_scope)
continue;
fib_alias_accessed(fa);