nl80211: Reset split_start when netlink skb is exhausted

When the netlink skb is exhausted split_start is left set. In the
subsequent retry, with a larger buffer, the dump is continued from the
failing point instead of from the beginning.

This was causing my rt28xx based USB dongle to now show up when
running "iw list" with an old iw version without split dump support.

Cc: stable@vger.kernel.org
Fixes: 3713b4e364ef ("nl80211: allow splitting wiphy information in dumps")
Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
[avoid the entire workaround when state->split is set]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 7a742594916e177461a5374693e78c07bcbce09b..6ea960b1a8eb776e69f34df3d22ec7b3c4c8de5b 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -1719,9 +1719,10 @@ static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
                                 * We can then retry with the larger buffer.
                                 */
                                if ((ret == -ENOBUFS || ret == -EMSGSIZE) &&
-                                   !skb->len &&
+                                   !skb->len && !state->split &&
                                    cb->min_dump_alloc < 4096) {
                                        cb->min_dump_alloc = 4096;
+                                       state->split_start = 0;
                                        rtnl_unlock();
                                        return 1;
                                }