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From:   Aleksandr Nogikh <aleksandrnogikh@gmail.com>
To:     davem@davemloft.net, kuba@kernel.org, johannes@sipsolutions.net
Cc:     edumazet@google.com, andreyknvl@google.com, dvyukov@google.com,
        elver@google.com, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
        willemdebruijn.kernel@gmail.com,
        Aleksandr Nogikh <nogikh@google.com>
Subject: [PATCH v5 3/3] mac80211: add KCOV remote annotations to incoming frame processing
Date:   Thu, 29 Oct 2020 17:36:20 +0000
Message-Id: <20201029173620.2121359-4-aleksandrnogikh@gmail.com>
In-Reply-To: <20201029173620.2121359-1-aleksandrnogikh@gmail.com>
References: <20201029173620.2121359-1-aleksandrnogikh@gmail.com>
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From: Aleksandr Nogikh <nogikh@google.com>

Add KCOV remote annotations to ieee80211_iface_work() and
ieee80211_rx_list(). This will enable coverage-guided fuzzing of
mac80211 code that processes incoming 802.11 frames.

Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
---
v4 -> v5:
* Using ieee80211_rx_list() instead of ieee80211_rx().
v1 -> v2:
* The commit now affects ieee80211_rx() instead of
  ieee80211_tasklet_handler().
---
 net/mac80211/iface.c |  2 ++
 net/mac80211/rx.c    | 16 +++++++++-------
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 1be775979132..56a1bcea2c1c 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1356,6 +1356,7 @@ static void ieee80211_iface_work(struct work_struct *work)
 	while ((skb = skb_dequeue(&sdata->skb_queue))) {
 		struct ieee80211_mgmt *mgmt = (void *)skb->data;
 
+		kcov_remote_start_common(skb_get_kcov_handle(skb));
 		if (ieee80211_is_action(mgmt->frame_control) &&
 		    mgmt->u.action.category == WLAN_CATEGORY_BACK) {
 			int len = skb->len;
@@ -1465,6 +1466,7 @@ static void ieee80211_iface_work(struct work_struct *work)
 		}
 
 		kfree_skb(skb);
+		kcov_remote_stop();
 	}
 
 	/* then other type-dependent work */
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 1e2e5a406d58..09d1c9fb8872 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -4742,6 +4742,8 @@ void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
 
 	status->rx_flags = 0;
 
+	kcov_remote_start_common(skb_get_kcov_handle(skb));
+
 	/*
 	 * Frames with failed FCS/PLCP checksum are not returned,
 	 * all other frames are returned without radiotap header
@@ -4749,15 +4751,15 @@ void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
 	 * Also, frames with less than 16 bytes are dropped.
 	 */
 	skb = ieee80211_rx_monitor(local, skb, rate);
-	if (!skb)
-		return;
-
-	ieee80211_tpt_led_trig_rx(local,
-			((struct ieee80211_hdr *)skb->data)->frame_control,
-			skb->len);
+	if (skb) {
+		ieee80211_tpt_led_trig_rx(local,
+					  ((struct ieee80211_hdr *)skb->data)->frame_control,
+					  skb->len);
 
-	__ieee80211_rx_handle_packet(hw, pubsta, skb, list);
+		__ieee80211_rx_handle_packet(hw, pubsta, skb, list);
+	}
 
+	kcov_remote_stop();
 	return;
  drop:
 	kfree_skb(skb);
-- 
2.29.1.341.ge80a0c044ae-goog