[ovs-dev] [PATCH] dpif-netlink: Fix dumping uninitialized netdev flow stats.

Ilya Maximets i.maximets at ovn.org
Sat Jan 4 00:44:18 UTC 2020

dpif logging functions expects to be called after the operation.
log_flow_del_message() dumps flow stats on success which are not
initialized before the actual call to netdev_flow_del():

 Conditional jump or move depends on uninitialised value(s)
    at 0x6090875: _itoa_word (_itoa.c:179)
    by 0x6093F0D: vfprintf (vfprintf.c:1642)
    by 0x60C090F: vsnprintf (vsnprintf.c:114)
    by 0xE5E7EC: ds_put_format_valist (dynamic-string.c:155)
    by 0xE5E755: ds_put_format (dynamic-string.c:142)
    by 0xE5A5E6: dpif_flow_stats_format (dpif.c:903)
    by 0xE5B708: log_flow_message (dpif.c:1763)
    by 0xE5BCA4: log_flow_del_message (dpif.c:1809)
    by 0xFA6076: try_send_to_netdev (dpif-netlink.c:2190)
    by 0xFA0D3C: dpif_netlink_operate (dpif-netlink.c:2248)
    by 0xE5AFAC: dpif_operate (dpif.c:1376)
    by 0xDF176E: push_dp_ops (ofproto-dpif-upcall.c:2367)
    by 0xDF04C8: push_ukey_ops (ofproto-dpif-upcall.c:2447)
    by 0xDF008F: revalidator_sweep__ (ofproto-dpif-upcall.c:2805)
    by 0xDF5DC6: revalidator_sweep (ofproto-dpif-upcall.c:2816)
    by 0xDF1E83: udpif_revalidator (ofproto-dpif-upcall.c:949)
    by 0xF3A3FE: ovsthread_wrapper (ovs-thread.c:383)
    by 0x565F6DA: start_thread (pthread_create.c:463)
    by 0x615988E: clone (clone.S:95)
  Uninitialised value was created by a stack allocation
    at 0xDEFC24: revalidator_sweep__ (ofproto-dpif-upcall.c:2733)

Also, by calling the log functions after the actual operation we could
pass the real error code instead of reporting success unconditionally.

CC: Roi Dayan <roid at mellanox.com>
Fixes: 3cd99886191e ("dpif-netlink: Use dpif logging functions")
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
 lib/dpif-netlink.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
index a08c2378a..25423e86c 100644
--- a/lib/dpif-netlink.c
+++ b/lib/dpif-netlink.c
@@ -2176,8 +2176,8 @@ try_send_to_netdev(struct dpif_netlink *dpif, struct dpif_op *op)
-        log_flow_put_message(&dpif->dpif, &this_module, put, 0);
         err = parse_flow_put(dpif, put);
+        log_flow_put_message(&dpif->dpif, &this_module, put, err);
     case DPIF_OP_FLOW_DEL: {
@@ -2187,9 +2187,9 @@ try_send_to_netdev(struct dpif_netlink *dpif, struct dpif_op *op)
-        log_flow_del_message(&dpif->dpif, &this_module, del, 0);
         err = netdev_ports_flow_del(dpif->dpif.dpif_class, del->ufid,
+        log_flow_del_message(&dpif->dpif, &this_module, del, err);
     case DPIF_OP_FLOW_GET: {
@@ -2199,8 +2199,8 @@ try_send_to_netdev(struct dpif_netlink *dpif, struct dpif_op *op)
-        log_flow_get_message(&dpif->dpif, &this_module, get, 0);
         err = parse_flow_get(dpif, get);
+        log_flow_get_message(&dpif->dpif, &this_module, get, err);
     case DPIF_OP_EXECUTE:

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