[ovs-dev] [PATCH] datapath: Fix unaligned access when storing stats.

[Jesse Gross]

Both datapath and vport stats contain 64-bit members in a struct
but we write them directly in Netlink attributes which only
guarantee 32-bit alignment.  This causes problems on RISC
architectures that care about alignment so this computes the stats
on the stack and then memcpy's them.

Signed-off-by: Jesse Gross <je...@nicira.com>
---
 datapath/datapath.c |   19 +++++++------------
 1 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/datapath/datapath.c b/datapath/datapath.c
index c43adf9..54248e2 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1261,7 +1261,7 @@ static int ovs_dp_cmd_fill_info(struct datapath *dp, 
struct sk_buff *skb,
                                u32 pid, u32 seq, u32 flags, u8 cmd)
 {
        struct ovs_header *ovs_header;
-       struct nlattr *nla;
+       struct ovs_dp_stats dp_stats;
        int err;
 
        ovs_header = genlmsg_put(skb, pid, seq, &dp_datapath_genl_family,
@@ -1277,10 +1277,8 @@ static int ovs_dp_cmd_fill_info(struct datapath *dp, 
struct sk_buff *skb,
        if (err)
                goto nla_put_failure;
 
-       nla = nla_reserve(skb, OVS_DP_ATTR_STATS, sizeof(struct ovs_dp_stats));
-       if (!nla)
-               goto nla_put_failure;
-       get_dp_stats(dp, nla_data(nla));
+       get_dp_stats(dp, &dp_stats);
+       NLA_PUT(skb, OVS_DP_ATTR_STATS, sizeof(struct ovs_dp_stats), &dp_stats);
 
        return genlmsg_end(skb, ovs_header);
 
@@ -1604,7 +1602,7 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, 
struct sk_buff *skb,
                                   u32 pid, u32 seq, u32 flags, u8 cmd)
 {
        struct ovs_header *ovs_header;
-       struct nlattr *nla;
+       struct ovs_vport_stats vport_stats;
        int err;
 
        ovs_header = genlmsg_put(skb, pid, seq, &dp_vport_genl_family,
@@ -1619,12 +1617,9 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, 
struct sk_buff *skb,
        NLA_PUT_STRING(skb, OVS_VPORT_ATTR_NAME, vport->ops->get_name(vport));
        NLA_PUT_U32(skb, OVS_VPORT_ATTR_UPCALL_PID, vport->upcall_pid);
 
-       nla = nla_reserve(skb, OVS_VPORT_ATTR_STATS,
-                         sizeof(struct ovs_vport_stats));
-       if (!nla)
-               goto nla_put_failure;
-
-       vport_get_stats(vport, nla_data(nla));
+       vport_get_stats(vport, &vport_stats);
+       NLA_PUT(skb, OVS_VPORT_ATTR_STATS, sizeof(struct ovs_vport_stats),
+               &vport_stats);
 
        NLA_PUT(skb, OVS_VPORT_ATTR_ADDRESS, ETH_ALEN,
                vport->ops->get_addr(vport));
-- 
1.7.5.4

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