[PATCH v2] station: cancel quick scans on Connect()

[PATCH v2] station: cancel quick scans on Connect()

[James Prestwood]

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At some point the non-interactive client tests began failing.
This was due to a bug in station where it would transition from
'connected' to 'autoconnect' due to a failed scan request. This
happened because a quick scan got scheduled during an ongoing
scan, then a Connect() gets issued. The work queue treats the
Connect as a priority so it delays the quick scan until after the
connection succeeds. This results in a failed quick scan which
IWD does not expect to happen when in a 'connected' state. This
failed scan actually triggers a state transition which then
gets IWD into a strange state where its connected from the
kernel point of view but does not think it is:

src/station.c:station_connect_cb() 13, result: 0
src/station.c:station_enter_state() Old State: connecting, new state: connected
src/wiphy.c:wiphy_radio_work_done() Work item 6 done
src/wiphy.c:wiphy_radio_work_next() Starting work item 5
src/station.c:station_quick_scan_triggered() Quick scan trigger failed: -95
src/station.c:station_enter_state() Old State: connected, new state: autoconnect_full

To fix this IWD should simply cancel any pending quick scans
if/when a Connect() call comes in.
---
 src/station.c | 6 ++++++
 1 file changed, 6 insertions(+)

v2:
 * Rather than handle inside the triggered callback we can
   just cancel the scan when the connection is attempted.
   This prevents unneeded kernel round trips as well.

diff --git a/src/station.c b/src/station.c
index b600f37e..55368472 100644
--- a/src/station.c
+++ b/src/station.c
@@ -2539,6 +2539,12 @@ void station_connect_network(struct station *station, struct network *network,
 				dbus_error_failed(station->hidden_pending));
 	}
 
+	if (station->quick_scan_id) {
+		scan_cancel(netdev_get_wdev_id(station->netdev),
+				station->quick_scan_id);
+		station->quick_scan_id = 0;
+	}
+
 	if (station_is_busy(station)) {
 		station_disconnect_onconnect(station, network, bss, message);
 
-- 
2.26.2

Re: [PATCH v2] station: cancel quick scans on Connect()

[Denis Kenzior]

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Hi James,

On 1/26/21 1:57 PM, James Prestwood wrote:
> At some point the non-interactive client tests began failing.
> This was due to a bug in station where it would transition from
> 'connected' to 'autoconnect' due to a failed scan request. This
> happened because a quick scan got scheduled during an ongoing
> scan, then a Connect() gets issued. The work queue treats the
> Connect as a priority so it delays the quick scan until after the
> connection succeeds. This results in a failed quick scan which
> IWD does not expect to happen when in a 'connected' state. This
> failed scan actually triggers a state transition which then
> gets IWD into a strange state where its connected from the
> kernel point of view but does not think it is:
> 
> src/station.c:station_connect_cb() 13, result: 0
> src/station.c:station_enter_state() Old State: connecting, new state: connected
> src/wiphy.c:wiphy_radio_work_done() Work item 6 done
> src/wiphy.c:wiphy_radio_work_next() Starting work item 5
> src/station.c:station_quick_scan_triggered() Quick scan trigger failed: -95
> src/station.c:station_enter_state() Old State: connected, new state: autoconnect_full
> 
> To fix this IWD should simply cancel any pending quick scans
> if/when a Connect() call comes in.
> ---
>   src/station.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> v2:
>   * Rather than handle inside the triggered callback we can
>     just cancel the scan when the connection is attempted.
>     This prevents unneeded kernel round trips as well.
> 

Applied, thanks.

Regards,
-Denis