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Message-Id: <20190919214805.117395564@linuxfoundation.org>
Date: Fri, 20 Sep 2019 00:03:24 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Li Shuang <shuali@...hat.com>,
Xin Long <lucien.xin@...il.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.9 11/74] tipc: add NULL pointer check before calling kfree_rcu
From: Xin Long <lucien.xin@...il.com>
[ Upstream commit 42dec1dbe38239cf91cc1f4df7830c66276ced37 ]
Unlike kfree(p), kfree_rcu(p, rcu) won't do NULL pointer check. When
tipc_nametbl_remove_publ returns NULL, the panic below happens:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000068
RIP: 0010:__call_rcu+0x1d/0x290
Call Trace:
<IRQ>
tipc_publ_notify+0xa9/0x170 [tipc]
tipc_node_write_unlock+0x8d/0x100 [tipc]
tipc_node_link_down+0xae/0x1d0 [tipc]
tipc_node_check_dest+0x3ea/0x8f0 [tipc]
? tipc_disc_rcv+0x2c7/0x430 [tipc]
tipc_disc_rcv+0x2c7/0x430 [tipc]
? tipc_rcv+0x6bb/0xf20 [tipc]
tipc_rcv+0x6bb/0xf20 [tipc]
? ip_route_input_slow+0x9cf/0xb10
tipc_udp_recv+0x195/0x1e0 [tipc]
? tipc_udp_is_known_peer+0x80/0x80 [tipc]
udp_queue_rcv_skb+0x180/0x460
udp_unicast_rcv_skb.isra.56+0x75/0x90
__udp4_lib_rcv+0x4ce/0xb90
ip_local_deliver_finish+0x11c/0x210
ip_local_deliver+0x6b/0xe0
? ip_rcv_finish+0xa9/0x410
ip_rcv+0x273/0x362
Fixes: 97ede29e80ee ("tipc: convert name table read-write lock to RCU")
Reported-by: Li Shuang <shuali@...hat.com>
Signed-off-by: Xin Long <lucien.xin@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
net/tipc/name_distr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/tipc/name_distr.c
+++ b/net/tipc/name_distr.c
@@ -224,7 +224,8 @@ static void tipc_publ_purge(struct net *
publ->key);
}
- kfree_rcu(p, rcu);
+ if (p)
+ kfree_rcu(p, rcu);
}
/**
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