cfg80211: fix race between core hint and driver's custom apply

Its possible for cfg80211 to have scheduled the work and for
the global workqueue to not have kicked in prior to a cfg80211
driver's regulatory hint or wiphy_apply_custom_regulatory().

Although this is very unlikely its possible and should fix
this race. When this race would happen you are expected to have
hit a null pointer dereference panic.

Cc: stable@kernel.org
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Tested-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 08265ca15785..487cb627ddba 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -1551,6 +1551,13 @@ static int regulatory_hint_core(const char *alpha2)
 
         queue_regulatory_request(request);
 
+        /*
+         * This ensures last_request is populated once modules
+         * come swinging in and calling regulatory hints and
+         * wiphy_apply_custom_regulatory().
+         */
+        flush_scheduled_work();
+
         return 0;
 }