netdev - [PATCH 48/65] staging: wfx: fix RCU usage

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Date:   Wed, 15 Jan 2020 12:13:12 +0000
From:   Jérôme Pouiller <Jerome.Pouiller@...abs.com>
To:     "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S . Miller" <davem@...emloft.net>,
        Jérôme Pouiller <Jerome.Pouiller@...abs.com>
Subject: [PATCH 48/65] staging: wfx: fix RCU usage

From: Jérôme Pouiller <jerome.pouiller@...abs.com>

Indeed, sta was used after call to rcu_unlock()

Signed-off-by: Jérôme Pouiller <jerome.pouiller@...abs.com>
---
 drivers/staging/wfx/sta.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
index 80a2a9e8256f..d50b583af187 100644
--- a/drivers/staging/wfx/sta.c
+++ b/drivers/staging/wfx/sta.c
@@ -690,10 +690,9 @@ static void wfx_join_finalize(struct wfx_vif *wvif,
 	struct ieee80211_sta *sta = NULL;
 
 	wvif->beacon_int = info->beacon_int;
-	rcu_read_lock();
+	rcu_read_lock(); // protect sta
 	if (info->bssid && !info->ibss_joined)
 		sta = ieee80211_find_sta(wvif->vif, info->bssid);
-	rcu_read_unlock();
 	if (sta)
 		wvif->bss_params.operational_rate_set =
 			wfx_rate_mask_to_hw(wvif->wdev, sta->supp_rates[wvif->channel->band]);
@@ -712,6 +711,7 @@ static void wfx_join_finalize(struct wfx_vif *wvif,
 	wvif->bss_params.aid = info->aid;
 
 	hif_set_association_mode(wvif, info, sta ? &sta->ht_cap : NULL);
+	rcu_read_unlock();
 
 	if (!info->ibss_joined) {
 		hif_keep_alive_period(wvif, 30 /* sec */);
-- 
2.25.0