From:   Luca Coelho <luca@coelho.fi>
To:     johannes@sipsolutions.net
Cc:     linux-wireless@vger.kernel.org, Lior Cohen <lior2.cohen@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>
Date:   Sat, 15 Dec 2018 11:03:02 +0200
Message-Id: <20181215090325.31604-2-luca@coelho.fi>
In-Reply-To: <20181215090325.31604-1-luca@coelho.fi>
References: <20181215090325.31604-1-luca@coelho.fi>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Subject: [PATCH 01/24] mac80211: suspicious RCU usage fix
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

From: Lior Cohen <lior2.cohen@intel.com>

Suspicious RCU usage observed while calling the
cfg80211_sta_opmode_change_notify() during rx_handlers path.
The issue occurred due to illegal blocking while in RCU read-side
critical section. The blocking caused by an attempt to alloc skb with the
GFP_KERNEL flag, which eventually call the might_sleep().

Signed-off-by: Lior Cohen <lior2.cohen@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
---
 net/mac80211/rx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 3bd3b5769797..a69ecfb212ed 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3063,7 +3063,7 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 			cfg80211_sta_opmode_change_notify(sdata->dev,
 							  rx->sta->addr,
 							  &sta_opmode,
-							  GFP_KERNEL);
+							  GFP_ATOMIC);
 			goto handled;
 		}
 		case WLAN_HT_ACTION_NOTIFY_CHANWIDTH: {
@@ -3100,7 +3100,7 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 			cfg80211_sta_opmode_change_notify(sdata->dev,
 							  rx->sta->addr,
 							  &sta_opmode,
-							  GFP_KERNEL);
+							  GFP_ATOMIC);
 			goto handled;
 		}
 		default:
-- 
2.19.2