[PATCH] net: mac80211: Add NULL checks for sta->sdata

[PATCH] net: mac80211: Add NULL checks for sta->sdata

[Jia-Ju Bai]

In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
should be checked before being used.

However, in the same call stack, sta->sdata is also used in the
following functions:

ieee80211_ba_session_work()
  ___ieee80211_stop_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    sdata_info(sta->sdata, ...); -> No check
    ieee80211_send_delba(sta->sdata, ...) -> No check
  ___ieee80211_start_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    ht_dbg_ratelimited(sta->sdata, ...); -> No check
  ieee80211_tx_ba_session_handle_start(sta)
    sdata = sta->sdata; if (!sdata) -> Add check by previous commit
  ___ieee80211_stop_tx_ba_session(sdata)
    ht_dbg(sta->sdata, ...); -> No check
  ieee80211_start_tx_ba_cb(sdata)
    sdata = sta->sdata; local = sdata->local -> No check
  ieee80211_stop_tx_ba_cb(sdata)
    ht_dbg(sta->sdata, ...); -> No check

Thus, to avoid possible null-pointer dereferences, the related checks
should be added.

These results are reported by a static tool designed by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reported-by: TOTE Robot <baijiaju@buaa.edu.cn>
---
 net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
 net/mac80211/agg-tx.c | 16 ++++++++--
 2 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index c6fa53230450..6616970785a2 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 	RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
 	__clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
 
-	ht_dbg(sta->sdata,
-	       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
-	       sta->sta.addr, tid,
-	       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
-	       (int)reason);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata,
+		       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
+		       sta->sta.addr, tid,
+		       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
+		       (int)reason);
+	}
 
-	if (drv_ampdu_action(local, sta->sdata, &params))
+	if (sta->sdata && drv_ampdu_action(local, sta->sdata, &params))
 		sdata_info(sta->sdata,
 			   "HW problem - can not stop rx aggregation for %pM tid %d\n",
 			   sta->sta.addr, tid);
 
 	/* check if this is a self generated aggregation halt */
-	if (initiator == WLAN_BACK_RECIPIENT && tx)
+	if (initiator == WLAN_BACK_RECIPIENT && tx && sta->sdata)
 		ieee80211_send_delba(sta->sdata, sta->sta.addr,
 				     tid, WLAN_BACK_RECIPIENT, reason);
 
@@ -279,17 +281,21 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (!sta->sta.deflink.ht_cap.ht_supported &&
 	    !sta->sta.deflink.he_cap.has_he) {
-		ht_dbg(sta->sdata,
-		       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
+			       sta->sta.addr, tid);
+		}
 		/* send a response anyway, it's an error case if we get here */
 		goto end;
 	}
 
 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
-		ht_dbg(sta->sdata,
-		       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
+			       sta->sta.addr, tid);
+		}
 		goto end;
 	}
 
@@ -322,8 +328,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		buf_size = sta->sta.max_rx_aggregation_subframes;
 	params.buf_size = buf_size;
 
-	ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
-	       buf_size, sta->sta.addr);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
+		       buf_size, sta->sta.addr);
+	}
 
 	/* examine state machine */
 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
@@ -332,9 +340,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
 			struct tid_ampdu_rx *tid_rx;
 
-			ht_dbg_ratelimited(sta->sdata,
-					   "updated AddBA Req from %pM on tid %u\n",
-					   sta->sta.addr, tid);
+			if (sta->sdata) {
+				ht_dbg_ratelimited(sta->sdata,
+						   "updated AddBA Req from %pM on tid %u\n",
+						   sta->sta.addr, tid);
+			}
 			/* We have no API to update the timeout value in the
 			 * driver so reject the timeout update if the timeout
 			 * changed. If it did not change, i.e., no real update,
@@ -350,9 +360,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 			goto end;
 		}
 
-		ht_dbg_ratelimited(sta->sdata,
-				   "unexpected AddBA Req from %pM on tid %u\n",
-				   sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg_ratelimited(sta->sdata,
+					   "unexpected AddBA Req from %pM on tid %u\n",
+					   sta->sta.addr, tid);
+		}
 
 		/* delete existing Rx BA session on the same tid */
 		___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
@@ -362,9 +374,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
 		ret = drv_ampdu_action(local, sta->sdata, &params);
-		ht_dbg(sta->sdata,
-		       "Rx A-MPDU request on %pM tid %d result %d\n",
-		       sta->sta.addr, tid, ret);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Rx A-MPDU request on %pM tid %d result %d\n",
+			       sta->sta.addr, tid, ret);
+		}
 		if (!ret)
 			status = WLAN_STATUS_SUCCESS;
 		goto end;
@@ -401,8 +415,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		__skb_queue_head_init(&tid_agg_rx->reorder_buf[i]);
 
 	ret = drv_ampdu_action(local, sta->sdata, &params);
-	ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
-	       sta->sta.addr, tid, ret);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
+		       sta->sta.addr, tid, ret);
+	}
 	if (ret) {
 		kfree(tid_agg_rx->reorder_buf);
 		kfree(tid_agg_rx->reorder_time);
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index f9514bacbd4a..03b31b6e7ac7 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 
 	spin_unlock_bh(&sta->lock);
 
-	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
-	       sta->sta.addr, tid);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
+		       sta->sta.addr, tid);
+	}
 
 	del_timer_sync(&tid_tx->addba_resp_timer);
 	del_timer_sync(&tid_tx->session_timer);
@@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
 			      struct tid_ampdu_tx *tid_tx)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
-	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_local *local;
+
+	if (!sdata)
+		return;
+
+	local = sdata->local;
 
 	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 		return;
@@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
 	bool send_delba = false;
 	bool start_txq = false;
 
+	if (!sdata)
+		return;
+
 	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
 	       sta->sta.addr, tid);
 
-- 
2.34.1

[PATCH] net: mac80211: Add NULL checks for sta->sdata

[Jia-Ju Bai]

In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
should be checked before being used.

However, in the same call stack, sta->sdata is also used in the
following functions:

ieee80211_ba_session_work()
  ___ieee80211_stop_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    sdata_info(sta->sdata, ...); -> No check
    ieee80211_send_delba(sta->sdata, ...) -> No check
  ___ieee80211_start_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    ht_dbg_ratelimited(sta->sdata, ...); -> No check
  ieee80211_tx_ba_session_handle_start(sta)
    sdata = sta->sdata; if (!sdata) -> Add check by previous commit
  ___ieee80211_stop_tx_ba_session(sdata)
    ht_dbg(sta->sdata, ...); -> No check
  ieee80211_start_tx_ba_cb(sdata)
    sdata = sta->sdata; local = sdata->local -> No check
  ieee80211_stop_tx_ba_cb(sdata)
    ht_dbg(sta->sdata, ...); -> No check

Thus, to avoid possible null-pointer dereferences, the related checks
should be added.

These results are reported by a static tool designed by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reported-by: TOTE Robot <baijiaju@buaa.edu.cn>
---
 net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
 net/mac80211/agg-tx.c | 16 ++++++++--
 2 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index c6fa53230450..6616970785a2 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 	RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
 	__clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
 
-	ht_dbg(sta->sdata,
-	       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
-	       sta->sta.addr, tid,
-	       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
-	       (int)reason);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata,
+		       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
+		       sta->sta.addr, tid,
+		       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
+		       (int)reason);
+	}
 
-	if (drv_ampdu_action(local, sta->sdata, &params))
+	if (sta->sdata && drv_ampdu_action(local, sta->sdata, &params))
 		sdata_info(sta->sdata,
 			   "HW problem - can not stop rx aggregation for %pM tid %d\n",
 			   sta->sta.addr, tid);
 
 	/* check if this is a self generated aggregation halt */
-	if (initiator == WLAN_BACK_RECIPIENT && tx)
+	if (initiator == WLAN_BACK_RECIPIENT && tx && sta->sdata)
 		ieee80211_send_delba(sta->sdata, sta->sta.addr,
 				     tid, WLAN_BACK_RECIPIENT, reason);
 
@@ -279,17 +281,21 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (!sta->sta.deflink.ht_cap.ht_supported &&
 	    !sta->sta.deflink.he_cap.has_he) {
-		ht_dbg(sta->sdata,
-		       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
+			       sta->sta.addr, tid);
+		}
 		/* send a response anyway, it's an error case if we get here */
 		goto end;
 	}
 
 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
-		ht_dbg(sta->sdata,
-		       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
+			       sta->sta.addr, tid);
+		}
 		goto end;
 	}
 
@@ -322,8 +328,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		buf_size = sta->sta.max_rx_aggregation_subframes;
 	params.buf_size = buf_size;
 
-	ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
-	       buf_size, sta->sta.addr);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
+		       buf_size, sta->sta.addr);
+	}
 
 	/* examine state machine */
 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
@@ -332,9 +340,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
 			struct tid_ampdu_rx *tid_rx;
 
-			ht_dbg_ratelimited(sta->sdata,
-					   "updated AddBA Req from %pM on tid %u\n",
-					   sta->sta.addr, tid);
+			if (sta->sdata) {
+				ht_dbg_ratelimited(sta->sdata,
+						   "updated AddBA Req from %pM on tid %u\n",
+						   sta->sta.addr, tid);
+			}
 			/* We have no API to update the timeout value in the
 			 * driver so reject the timeout update if the timeout
 			 * changed. If it did not change, i.e., no real update,
@@ -350,9 +360,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 			goto end;
 		}
 
-		ht_dbg_ratelimited(sta->sdata,
-				   "unexpected AddBA Req from %pM on tid %u\n",
-				   sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg_ratelimited(sta->sdata,
+					   "unexpected AddBA Req from %pM on tid %u\n",
+					   sta->sta.addr, tid);
+		}
 
 		/* delete existing Rx BA session on the same tid */
 		___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
@@ -362,9 +374,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
 		ret = drv_ampdu_action(local, sta->sdata, &params);
-		ht_dbg(sta->sdata,
-		       "Rx A-MPDU request on %pM tid %d result %d\n",
-		       sta->sta.addr, tid, ret);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Rx A-MPDU request on %pM tid %d result %d\n",
+			       sta->sta.addr, tid, ret);
+		}
 		if (!ret)
 			status = WLAN_STATUS_SUCCESS;
 		goto end;
@@ -401,8 +415,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		__skb_queue_head_init(&tid_agg_rx->reorder_buf[i]);
 
 	ret = drv_ampdu_action(local, sta->sdata, &params);
-	ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
-	       sta->sta.addr, tid, ret);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
+		       sta->sta.addr, tid, ret);
+	}
 	if (ret) {
 		kfree(tid_agg_rx->reorder_buf);
 		kfree(tid_agg_rx->reorder_time);
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index f9514bacbd4a..03b31b6e7ac7 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 
 	spin_unlock_bh(&sta->lock);
 
-	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
-	       sta->sta.addr, tid);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
+		       sta->sta.addr, tid);
+	}
 
 	del_timer_sync(&tid_tx->addba_resp_timer);
 	del_timer_sync(&tid_tx->session_timer);
@@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
 			      struct tid_ampdu_tx *tid_tx)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
-	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_local *local;
+
+	if (!sdata)
+		return;
+
+	local = sdata->local;
 
 	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 		return;
@@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
 	bool send_delba = false;
 	bool start_txq = false;
 
+	if (!sdata)
+		return;
+
 	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
 	       sta->sta.addr, tid);
 
-- 
2.34.1

[PATCH] net: mac80211: Add NULL checks for sta->sdata

[Jia-Ju Bai]

From: Jia-Ju Bai <baijiaju@buaa.edu.cn>

In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
should be checked before being used.

However, in the same call stack, sta->sdata is also used in the
following functions:

ieee80211_ba_session_work()
  ___ieee80211_stop_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    sdata_info(sta->sdata, ...); -> No check
    ieee80211_send_delba(sta->sdata, ...) -> No check
  ___ieee80211_start_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    ht_dbg_ratelimited(sta->sdata, ...); -> No check
  ieee80211_tx_ba_session_handle_start(sta)
    sdata = sta->sdata; if (!sdata) -> Add check by previous commit
  ___ieee80211_stop_tx_ba_session(sdata)
    ht_dbg(sta->sdata, ...); -> No check
  ieee80211_start_tx_ba_cb(sdata)
    sdata = sta->sdata; local = sdata->local -> No check
  ieee80211_stop_tx_ba_cb(sdata)
    ht_dbg(sta->sdata, ...); -> No check

Thus, to avoid possible null-pointer dereferences, the related checks
should be added.

These results are reported by a static tool designed by myself.

Signed-off-by: Jia-Ju Bai <baijiaju@buaa.edu.cn>
---
 net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
 net/mac80211/agg-tx.c | 16 ++++++++--
 2 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index c6fa53230450..6616970785a2 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 	RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
 	__clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
 
-	ht_dbg(sta->sdata,
-	       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
-	       sta->sta.addr, tid,
-	       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
-	       (int)reason);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata,
+		       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
+		       sta->sta.addr, tid,
+		       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
+		       (int)reason);
+	}
 
-	if (drv_ampdu_action(local, sta->sdata, &params))
+	if (sta->sdata && drv_ampdu_action(local, sta->sdata, &params))
 		sdata_info(sta->sdata,
 			   "HW problem - can not stop rx aggregation for %pM tid %d\n",
 			   sta->sta.addr, tid);
 
 	/* check if this is a self generated aggregation halt */
-	if (initiator == WLAN_BACK_RECIPIENT && tx)
+	if (initiator == WLAN_BACK_RECIPIENT && tx && sta->sdata)
 		ieee80211_send_delba(sta->sdata, sta->sta.addr,
 				     tid, WLAN_BACK_RECIPIENT, reason);
 
@@ -279,17 +281,21 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (!sta->sta.deflink.ht_cap.ht_supported &&
 	    !sta->sta.deflink.he_cap.has_he) {
-		ht_dbg(sta->sdata,
-		       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
+			       sta->sta.addr, tid);
+		}
 		/* send a response anyway, it's an error case if we get here */
 		goto end;
 	}
 
 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
-		ht_dbg(sta->sdata,
-		       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
+			       sta->sta.addr, tid);
+		}
 		goto end;
 	}
 
@@ -322,8 +328,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		buf_size = sta->sta.max_rx_aggregation_subframes;
 	params.buf_size = buf_size;
 
-	ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
-	       buf_size, sta->sta.addr);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
+		       buf_size, sta->sta.addr);
+	}
 
 	/* examine state machine */
 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
@@ -332,9 +340,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
 			struct tid_ampdu_rx *tid_rx;
 
-			ht_dbg_ratelimited(sta->sdata,
-					   "updated AddBA Req from %pM on tid %u\n",
-					   sta->sta.addr, tid);
+			if (sta->sdata) {
+				ht_dbg_ratelimited(sta->sdata,
+						   "updated AddBA Req from %pM on tid %u\n",
+						   sta->sta.addr, tid);
+			}
 			/* We have no API to update the timeout value in the
 			 * driver so reject the timeout update if the timeout
 			 * changed. If it did not change, i.e., no real update,
@@ -350,9 +360,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 			goto end;
 		}
 
-		ht_dbg_ratelimited(sta->sdata,
-				   "unexpected AddBA Req from %pM on tid %u\n",
-				   sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg_ratelimited(sta->sdata,
+					   "unexpected AddBA Req from %pM on tid %u\n",
+					   sta->sta.addr, tid);
+		}
 
 		/* delete existing Rx BA session on the same tid */
 		___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
@@ -362,9 +374,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
 		ret = drv_ampdu_action(local, sta->sdata, &params);
-		ht_dbg(sta->sdata,
-		       "Rx A-MPDU request on %pM tid %d result %d\n",
-		       sta->sta.addr, tid, ret);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Rx A-MPDU request on %pM tid %d result %d\n",
+			       sta->sta.addr, tid, ret);
+		}
 		if (!ret)
 			status = WLAN_STATUS_SUCCESS;
 		goto end;
@@ -401,8 +415,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		__skb_queue_head_init(&tid_agg_rx->reorder_buf[i]);
 
 	ret = drv_ampdu_action(local, sta->sdata, &params);
-	ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
-	       sta->sta.addr, tid, ret);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
+		       sta->sta.addr, tid, ret);
+	}
 	if (ret) {
 		kfree(tid_agg_rx->reorder_buf);
 		kfree(tid_agg_rx->reorder_time);
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index f9514bacbd4a..03b31b6e7ac7 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 
 	spin_unlock_bh(&sta->lock);
 
-	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
-	       sta->sta.addr, tid);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
+		       sta->sta.addr, tid);
+	}
 
 	del_timer_sync(&tid_tx->addba_resp_timer);
 	del_timer_sync(&tid_tx->session_timer);
@@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
 			      struct tid_ampdu_tx *tid_tx)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
-	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_local *local;
+
+	if (!sdata)
+		return;
+
+	local = sdata->local;
 
 	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 		return;
@@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
 	bool send_delba = false;
 	bool start_txq = false;
 
+	if (!sdata)
+		return;
+
 	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
 	       sta->sta.addr, tid);
 
-- 
2.34.1

[PATCH] net: mac80211: Add NULL checks for sta->sdata

[Jia-Ju Bai]

In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
should be checked before being used.

However, in the same call stack, sta->sdata is also used in the
following functions:

ieee80211_ba_session_work()
  ___ieee80211_stop_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    sdata_info(sta->sdata, ...); -> No check
    ieee80211_send_delba(sta->sdata, ...) -> No check
  ___ieee80211_start_rx_ba_session(sta)
    ht_dbg(sta->sdata, ...); -> No check
    ht_dbg_ratelimited(sta->sdata, ...); -> No check
  ieee80211_tx_ba_session_handle_start(sta)
    sdata = sta->sdata; if (!sdata) -> Add check by previous commit
  ___ieee80211_stop_tx_ba_session(sdata)
    ht_dbg(sta->sdata, ...); -> No check
  ieee80211_start_tx_ba_cb(sdata)
    sdata = sta->sdata; local = sdata->local -> No check
  ieee80211_stop_tx_ba_cb(sdata)
    ht_dbg(sta->sdata, ...); -> No check

Thus, to avoid possible null-pointer dereferences, the related checks
should be added.

These results are reported by a static tool designed by myself.

Signed-off-by: Jia-Ju Bai <baijiaju@buaa.edu.cn>
---
 net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
 net/mac80211/agg-tx.c | 16 ++++++++--
 2 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index c6fa53230450..6616970785a2 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 	RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
 	__clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
 
-	ht_dbg(sta->sdata,
-	       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
-	       sta->sta.addr, tid,
-	       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
-	       (int)reason);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata,
+		       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
+		       sta->sta.addr, tid,
+		       initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
+		       (int)reason);
+	}
 
-	if (drv_ampdu_action(local, sta->sdata, &params))
+	if (sta->sdata && drv_ampdu_action(local, sta->sdata, &params))
 		sdata_info(sta->sdata,
 			   "HW problem - can not stop rx aggregation for %pM tid %d\n",
 			   sta->sta.addr, tid);
 
 	/* check if this is a self generated aggregation halt */
-	if (initiator == WLAN_BACK_RECIPIENT && tx)
+	if (initiator == WLAN_BACK_RECIPIENT && tx && sta->sdata)
 		ieee80211_send_delba(sta->sdata, sta->sta.addr,
 				     tid, WLAN_BACK_RECIPIENT, reason);
 
@@ -279,17 +281,21 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (!sta->sta.deflink.ht_cap.ht_supported &&
 	    !sta->sta.deflink.he_cap.has_he) {
-		ht_dbg(sta->sdata,
-		       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
+			       sta->sta.addr, tid);
+		}
 		/* send a response anyway, it's an error case if we get here */
 		goto end;
 	}
 
 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
-		ht_dbg(sta->sdata,
-		       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
-		       sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
+			       sta->sta.addr, tid);
+		}
 		goto end;
 	}
 
@@ -322,8 +328,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		buf_size = sta->sta.max_rx_aggregation_subframes;
 	params.buf_size = buf_size;
 
-	ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
-	       buf_size, sta->sta.addr);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
+		       buf_size, sta->sta.addr);
+	}
 
 	/* examine state machine */
 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
@@ -332,9 +340,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
 			struct tid_ampdu_rx *tid_rx;
 
-			ht_dbg_ratelimited(sta->sdata,
-					   "updated AddBA Req from %pM on tid %u\n",
-					   sta->sta.addr, tid);
+			if (sta->sdata) {
+				ht_dbg_ratelimited(sta->sdata,
+						   "updated AddBA Req from %pM on tid %u\n",
+						   sta->sta.addr, tid);
+			}
 			/* We have no API to update the timeout value in the
 			 * driver so reject the timeout update if the timeout
 			 * changed. If it did not change, i.e., no real update,
@@ -350,9 +360,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 			goto end;
 		}
 
-		ht_dbg_ratelimited(sta->sdata,
-				   "unexpected AddBA Req from %pM on tid %u\n",
-				   sta->sta.addr, tid);
+		if (sta->sdata) {
+			ht_dbg_ratelimited(sta->sdata,
+					   "unexpected AddBA Req from %pM on tid %u\n",
+					   sta->sta.addr, tid);
+		}
 
 		/* delete existing Rx BA session on the same tid */
 		___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
@@ -362,9 +374,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 
 	if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
 		ret = drv_ampdu_action(local, sta->sdata, &params);
-		ht_dbg(sta->sdata,
-		       "Rx A-MPDU request on %pM tid %d result %d\n",
-		       sta->sta.addr, tid, ret);
+		if (sta->sdata) {
+			ht_dbg(sta->sdata,
+			       "Rx A-MPDU request on %pM tid %d result %d\n",
+			       sta->sta.addr, tid, ret);
+		}
 		if (!ret)
 			status = WLAN_STATUS_SUCCESS;
 		goto end;
@@ -401,8 +415,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 		__skb_queue_head_init(&tid_agg_rx->reorder_buf[i]);
 
 	ret = drv_ampdu_action(local, sta->sdata, &params);
-	ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
-	       sta->sta.addr, tid, ret);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
+		       sta->sta.addr, tid, ret);
+	}
 	if (ret) {
 		kfree(tid_agg_rx->reorder_buf);
 		kfree(tid_agg_rx->reorder_time);
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index f9514bacbd4a..03b31b6e7ac7 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 
 	spin_unlock_bh(&sta->lock);
 
-	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
-	       sta->sta.addr, tid);
+	if (sta->sdata) {
+		ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
+		       sta->sta.addr, tid);
+	}
 
 	del_timer_sync(&tid_tx->addba_resp_timer);
 	del_timer_sync(&tid_tx->session_timer);
@@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
 			      struct tid_ampdu_tx *tid_tx)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
-	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_local *local;
+
+	if (!sdata)
+		return;
+
+	local = sdata->local;
 
 	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 		return;
@@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
 	bool send_delba = false;
 	bool start_txq = false;
 
+	if (!sdata)
+		return;
+
 	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
 	       sta->sta.addr, tid);
 
-- 
2.34.1

Re: [PATCH] net: mac80211: Add NULL checks for sta->sdata

[Simon Horman]

On Mon, Mar 20, 2023 at 09:35:33PM +0800, Jia-Ju Bai wrote:
> In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
> should be checked before being used.

Please run checkpatch on this patch, and correct the commit description
style.

./scripts/checkpatch.pl -g HEAD
ERROR: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'commit 69403bad97aa ("wifi: mac80211: sdata can be NULL during AMPDU start")'
#6:
In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it

> 
> However, in the same call stack, sta->sdata is also used in the
> following functions:
> 
> ieee80211_ba_session_work()
>   ___ieee80211_stop_rx_ba_session(sta)
>     ht_dbg(sta->sdata, ...); -> No check
>     sdata_info(sta->sdata, ...); -> No check
>     ieee80211_send_delba(sta->sdata, ...) -> No check
>   ___ieee80211_start_rx_ba_session(sta)
>     ht_dbg(sta->sdata, ...); -> No check
>     ht_dbg_ratelimited(sta->sdata, ...); -> No check
>   ieee80211_tx_ba_session_handle_start(sta)
>     sdata = sta->sdata; if (!sdata) -> Add check by previous commit
>   ___ieee80211_stop_tx_ba_session(sdata)
>     ht_dbg(sta->sdata, ...); -> No check
>   ieee80211_start_tx_ba_cb(sdata)
>     sdata = sta->sdata; local = sdata->local -> No check
>   ieee80211_stop_tx_ba_cb(sdata)
>     ht_dbg(sta->sdata, ...); -> No check

I wonder if it would be better to teach ht_* do do nothing
if the first argument is NULL.

Also, are these theoretical bugs?
Or something that has been observed?
And has a reproducer?

> Thus, to avoid possible null-pointer dereferences, the related checks
> should be added.
> 
> These results are reported by a static tool designed by myself.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> Reported-by: TOTE Robot <baijiaju@buaa.edu.cn>

I see 4 copies of this patch in a few minutes.
As per the FAQ [1], please leave at least 24h between posts of a patch.

[1] https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

Re: [PATCH] net: mac80211: Add NULL checks for sta->sdata

[Jia-Ju Bai]

Hello Simon,

Thanks for the reply!


On 2023/3/21 0:49, Simon Horman wrote:
> On Mon, Mar 20, 2023 at 09:35:33PM +0800, Jia-Ju Bai wrote:
>> In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
>> should be checked before being used.
> Please run checkpatch on this patch, and correct the commit description
> style.
>
> ./scripts/checkpatch.pl -g HEAD
> ERROR: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'commit 69403bad97aa ("wifi: mac80211: sdata can be NULL during AMPDU start")'
> #6:
> In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it

Okay, I will revise it and run checkpatch.

>
>> However, in the same call stack, sta->sdata is also used in the
>> following functions:
>>
>> ieee80211_ba_session_work()
>>    ___ieee80211_stop_rx_ba_session(sta)
>>      ht_dbg(sta->sdata, ...); -> No check
>>      sdata_info(sta->sdata, ...); -> No check
>>      ieee80211_send_delba(sta->sdata, ...) -> No check
>>    ___ieee80211_start_rx_ba_session(sta)
>>      ht_dbg(sta->sdata, ...); -> No check
>>      ht_dbg_ratelimited(sta->sdata, ...); -> No check
>>    ieee80211_tx_ba_session_handle_start(sta)
>>      sdata = sta->sdata; if (!sdata) -> Add check by previous commit
>>    ___ieee80211_stop_tx_ba_session(sdata)
>>      ht_dbg(sta->sdata, ...); -> No check
>>    ieee80211_start_tx_ba_cb(sdata)
>>      sdata = sta->sdata; local = sdata->local -> No check
>>    ieee80211_stop_tx_ba_cb(sdata)
>>      ht_dbg(sta->sdata, ...); -> No check
> I wonder if it would be better to teach ht_* do do nothing
> if the first argument is NULL.

Okay, I will use this way in patch v2.

>
> Also, are these theoretical bugs?
> Or something that has been observed?
> And has a reproducer?

These bugs are found by my static analysis tool, by extending a known 
bug fixed in a previous commit 69403bad97aa.
Thus, they could be theoretical bugs.

>
>> Thus, to avoid possible null-pointer dereferences, the related checks
>> should be added.
>>
>> These results are reported by a static tool designed by myself.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>> Reported-by: TOTE Robot <baijiaju@buaa.edu.cn>
> I see 4 copies of this patch in a few minutes.
> As per the FAQ [1], please leave at least 24h between posts of a patch.
>
> [1] https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

I am quite sorry for this, because my script of git send email was buggy.
I noticed this problem after sending the e-mail, and now I have fixed it :)


Best wishes,
Jia-Ju Bai

Re: [PATCH] net: mac80211: Add NULL checks for sta->sdata

[Simon Horman]

On Tue, Mar 21, 2023 at 03:40:40PM +0800, Jia-Ju Bai wrote:
> Hello Simon,
> 
> Thanks for the reply!
> 
> 
> On 2023/3/21 0:49, Simon Horman wrote:
> > On Mon, Mar 20, 2023 at 09:35:33PM +0800, Jia-Ju Bai wrote:
> > > In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
> > > should be checked before being used.
> > Please run checkpatch on this patch, and correct the commit description
> > style.
> > 
> > ./scripts/checkpatch.pl -g HEAD
> > ERROR: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'commit 69403bad97aa ("wifi: mac80211: sdata can be NULL during AMPDU start")'
> > #6:
> > In a previous commit 69403bad97aa, sta->sdata can be NULL, and thus it
> 
> Okay, I will revise it and run checkpatch.

Thanks.

> > > However, in the same call stack, sta->sdata is also used in the
> > > following functions:
> > > 
> > > ieee80211_ba_session_work()
> > >    ___ieee80211_stop_rx_ba_session(sta)
> > >      ht_dbg(sta->sdata, ...); -> No check
> > >      sdata_info(sta->sdata, ...); -> No check
> > >      ieee80211_send_delba(sta->sdata, ...) -> No check
> > >    ___ieee80211_start_rx_ba_session(sta)
> > >      ht_dbg(sta->sdata, ...); -> No check
> > >      ht_dbg_ratelimited(sta->sdata, ...); -> No check
> > >    ieee80211_tx_ba_session_handle_start(sta)
> > >      sdata = sta->sdata; if (!sdata) -> Add check by previous commit
> > >    ___ieee80211_stop_tx_ba_session(sdata)
> > >      ht_dbg(sta->sdata, ...); -> No check
> > >    ieee80211_start_tx_ba_cb(sdata)
> > >      sdata = sta->sdata; local = sdata->local -> No check
> > >    ieee80211_stop_tx_ba_cb(sdata)
> > >      ht_dbg(sta->sdata, ...); -> No check
> > I wonder if it would be better to teach ht_* do do nothing
> > if the first argument is NULL.
> 
> Okay, I will use this way in patch v2.

Maybe it is not a good idea.
But I think it is worth trying, at least locally, to see how it goes.

> > Also, are these theoretical bugs?
> > Or something that has been observed?
> > And has a reproducer?
> 
> These bugs are found by my static analysis tool, by extending a known bug
> fixed in a previous commit 69403bad97aa.
> Thus, they could be theoretical bugs.

Thanks, understood.
I think it would be worth making that a bit clearer in the
patch description (commit message).

> > > Thus, to avoid possible null-pointer dereferences, the related checks
> > > should be added.
> > > 
> > > These results are reported by a static tool designed by myself.
> > > 
> > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> > > Reported-by: TOTE Robot <baijiaju@buaa.edu.cn>
> > I see 4 copies of this patch in a few minutes.
> > As per the FAQ [1], please leave at least 24h between posts of a patch.
> > 
> > [1] https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html
> 
> I am quite sorry for this, because my script of git send email was buggy.
> I noticed this problem after sending the e-mail, and now I have fixed it :)

Thanks, I realised after I sent my previous email that something like that
might have happened. Thanks for fixing it.

Re: [PATCH] net: mac80211: Add NULL checks for sta->sdata

[Jia-Ju Bai]

On 2023/3/21 16:36, Simon Horman wrote:
>>>> However, in the same call stack, sta->sdata is also used in the
>>>> following functions:
>>>>
>>>> ieee80211_ba_session_work()
>>>>     ___ieee80211_stop_rx_ba_session(sta)
>>>>       ht_dbg(sta->sdata, ...); -> No check
>>>>       sdata_info(sta->sdata, ...); -> No check
>>>>       ieee80211_send_delba(sta->sdata, ...) -> No check
>>>>     ___ieee80211_start_rx_ba_session(sta)
>>>>       ht_dbg(sta->sdata, ...); -> No check
>>>>       ht_dbg_ratelimited(sta->sdata, ...); -> No check
>>>>     ieee80211_tx_ba_session_handle_start(sta)
>>>>       sdata = sta->sdata; if (!sdata) -> Add check by previous commit
>>>>     ___ieee80211_stop_tx_ba_session(sdata)
>>>>       ht_dbg(sta->sdata, ...); -> No check
>>>>     ieee80211_start_tx_ba_cb(sdata)
>>>>       sdata = sta->sdata; local = sdata->local -> No check
>>>>     ieee80211_stop_tx_ba_cb(sdata)
>>>>       ht_dbg(sta->sdata, ...); -> No check
>>> I wonder if it would be better to teach ht_* do do nothing
>>> if the first argument is NULL.
>> Okay, I will use this way in patch v2.
> Maybe it is not a good idea.
> But I think it is worth trying, at least locally, to see how it goes.

After checking the code, I find that ht_* is actually a macro from _sdata_*.
Many code points use ht_* and _sdata_*, and thus I am not sure it is 
fine to try this way.

For simplification, I still think checking sdata before the calls to 
ht_* or _sdata_* should be more proper :)

>
>>> Also, are these theoretical bugs?
>>> Or something that has been observed?
>>> And has a reproducer?
>> These bugs are found by my static analysis tool, by extending a known bug
>> fixed in a previous commit 69403bad97aa.
>> Thus, they could be theoretical bugs.
> Thanks, understood.
> I think it would be worth making that a bit clearer in the
> patch description (commit message).

Okay.

I have sent the v2 patch, please have a look.
Thanks a lot :)


Best wishes,
Jia-Ju Bai