* [PATCH net] tipc: add NULL pointer check before calling kfree_rcu
@ 2019-09-03 9:53 Xin Long
2019-09-05 7:59 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Xin Long @ 2019-09-03 9:53 UTC (permalink / raw)
To: network dev; +Cc: davem, Jon Maloy, Ying Xue, tipc-discussion
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@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
net/tipc/name_distr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c
index 44abc8e..241ed22 100644
--- a/net/tipc/name_distr.c
+++ b/net/tipc/name_distr.c
@@ -223,7 +223,8 @@ static void tipc_publ_purge(struct net *net, struct publication *publ, u32 addr)
publ->key);
}
- kfree_rcu(p, rcu);
+ if (p)
+ kfree_rcu(p, rcu);
}
/**
--
2.1.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] tipc: add NULL pointer check before calling kfree_rcu
2019-09-03 9:53 [PATCH net] tipc: add NULL pointer check before calling kfree_rcu Xin Long
@ 2019-09-05 7:59 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-09-05 7:59 UTC (permalink / raw)
To: lucien.xin; +Cc: netdev, jon.maloy, ying.xue, tipc-discussion
From: Xin Long <lucien.xin@gmail.com>
Date: Tue, 3 Sep 2019 17:53:12 +0800
> Unlike kfree(p), kfree_rcu(p, rcu) won't do NULL pointer check. When
> tipc_nametbl_remove_publ returns NULL, the panic below happens:
...
> Fixes: 97ede29e80ee ("tipc: convert name table read-write lock to RCU")
> Reported-by: Li Shuang <shuali@redhat.com>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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