[PATCH 13/19] staging: wfx: fix potential dead lock between join and scan

Jerome Pouiller
2020-05-15T08:35:21Z

The device disallows to start a scan request between hif_join() and
hif_set_bss_params(). The driver is not protected against that. The
worst case happens when association is aborted and hif_set_bss_params()
never happens.

mac80211 would never ask for scan during the association process. So,
this patch just aborts the association in progress when scan is
requested.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
---
drivers/staging/wfx/scan.c | 5 +++++
drivers/staging/wfx/sta.c | 3 +++
drivers/staging/wfx/wfx.h | 2 ++
3 files changed, 10 insertions(+)

diff --git a/drivers/staging/wfx/scan.c b/drivers/staging/wfx/scan.c
index bf7ddc75c7db..e9de19784865 100644
--- a/drivers/staging/wfx/scan.c
+++ b/drivers/staging/wfx/scan.c
@@ -90,6 +90,11 @@ void wfx_hw_scan_work(struct work_struct *work)

mutex_lock(&wvif->wdev->conf_mutex);
mutex_lock(&wvif->scan_lock);
+ if (wvif->join_in_progress) {
+ dev_info(wvif->wdev->dev, "%s: abort in-progress REQ_JOIN",
+ __func__);
+ wfx_reset(wvif);
+ }
update_probe_tmpl(wvif, &hw_req->req);
chan_cur = 0;
do {
diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
index 7d9f680ca53a..6e9f38d051ab 100644
--- a/drivers/staging/wfx/sta.c
+++ b/drivers/staging/wfx/sta.c
@@ -353,6 +353,7 @@ void wfx_reset(struct wfx_vif *wvif)
if (wvif_count(wvif->wdev) <= 1)
hif_set_block_ack_policy(wvif, 0xFF, 0xFF);
wfx_tx_unlock(wvif->wdev);
+ wvif->join_in_progress = false;
wvif->bss_not_support_ps_poll = false;
cancel_delayed_work_sync(&wvif->beacon_loss_work);
}
@@ -390,6 +391,7 @@ static void wfx_do_join(struct wfx_vif *wvif)
wfx_set_mfp(wvif, bss);
cfg80211_put_bss(wvif->wdev->hw->wiphy, bss);

+ wvif->join_in_progress = true;
ret = hif_join(wvif, conf, wvif->channel, ssid, ssidlen);
if (ret) {
ieee80211_connection_loss(wvif->vif);
@@ -485,6 +487,7 @@ void wfx_stop_ap(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
static void wfx_join_finalize(struct wfx_vif *wvif,
struct ieee80211_bss_conf *info)
{
+ wvif->join_in_progress = false;
hif_set_association_mode(wvif, info);
hif_keep_alive_period(wvif, 0);
// beacon_loss_count is defined to 7 in net/mac80211/mlme.c. Let's use
diff --git a/drivers/staging/wfx/wfx.h b/drivers/staging/wfx/wfx.h
index 09a24561f092..cc9f7d16ee8b 100644
--- a/drivers/staging/wfx/wfx.h
+++ b/drivers/staging/wfx/wfx.h
@@ -69,6 +69,8 @@ struct wfx_vif {
u32 link_id_map;

bool after_dtim_tx_allowed;
+ bool join_in_progress;
+
struct delayed_work beacon_loss_work;

struct tx_policy_cache tx_policy_cache;
--
2.26.2