From: Frank Blaschka <frank.blaschka@xxxxxxxxxx>
when use dst_get_neighbour to get neighbour, we need
rcu_read_lock to protect, since dst_get_neighbour uses
rcu_dereference.
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
include/net/dst.h:91 invoked rcu_dereference_check() without protection!
...
Call Trace:
([<0000000000011ad8>] show_trace+0x158/0x15c)
[<00000000003c395a>] qeth_l3_hard_start_xmit+0x212/0xb2c
[<00000000004006ac>] dev_hard_start_xmit+0x444/0x9bc
[<000000000041effa>] sch_direct_xmit+0xd2/0x328
[<000000000041f32a>] __qdisc_run+0xda/0x198
[<00000000003f84b6>] net_tx_action+0x152/0x360
[<000000000005798e>] __do_softirq+0xee/0x3b0
[<0000000000021330>] do_softirq+0xac/0x100
([<00000000000212f2>] do_softirq+0x6e/0x100)
[<0000000000057142>] local_bh_enable_ip+0x11a/0x120
[<000000000043ff50>] tcp_sendmsg+0x21c/0xe08
[<00000000003dfcdc>] sock_sendmsg+0xc8/0x100
[<00000000003e3d98>] SyS_sendto+0x108/0x140
[<00000000003e3e1c>] SyS_send+0x4c/0x5c
[<00000000003e4b62>] SyS_socketcall+0x206/0x348
[<00000000004e95ca>] sysc_noemu+0x16/0x1c
[<0000004a2a87dbb0>] 0x4a2a87dbb0
INFO: lockdep is turned off.
Signed-off-by: Frank Blaschka <frank.blaschka@xxxxxxxxxx>
---
drivers/s390/net/qeth_l3_main.c | 7 +++++++
1 file changed, 7 insertions(+)
diff -urpN linux-2.6/drivers/s390/net/qeth_l3_main.c linux-2.6-patched/drivers/s390/net/qeth_l3_main.c
--- linux-2.6/drivers/s390/net/qeth_l3_main.c 2011-11-14 18:26:56.000000000 +0100
+++ linux-2.6-patched/drivers/s390/net/qeth_l3_main.c 2011-11-14 18:27:18.000000000 +0100
@@ -2756,11 +2756,13 @@ int inline qeth_l3_get_cast_type(struct
struct neighbour *n = NULL;
struct dst_entry *dst;
+ rcu_read_lock();
dst = skb_dst(skb);
if (dst)
n = dst_get_neighbour(dst);
if (n) {
cast_type = n->type;
+ rcu_read_unlock();
if ((cast_type == RTN_BROADCAST) ||
(cast_type == RTN_MULTICAST) ||
(cast_type == RTN_ANYCAST))
@@ -2768,6 +2770,8 @@ int inline qeth_l3_get_cast_type(struct
else
return RTN_UNSPEC;
}
+ rcu_read_unlock();
+
/* try something else */
if (skb->protocol == ETH_P_IPV6)
return (skb_network_header(skb)[24] == 0xff) ?
@@ -2847,6 +2851,8 @@ static void qeth_l3_fill_header(struct q
}
hdr->hdr.l3.length = skb->len - sizeof(struct qeth_hdr);
+
+ rcu_read_lock();
dst = skb_dst(skb);
if (dst)
n = dst_get_neighbour(dst);
@@ -2893,6 +2899,7 @@ static void qeth_l3_fill_header(struct q
QETH_CAST_UNICAST | QETH_HDR_PASSTHRU;
}
}
+ rcu_read_unlock();
}
static inline void qeth_l3_hdr_csum(struct qeth_card *card,
--
To unsubscribe from this list: send the line "unsubscribe linux-s390" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
