Date:   Wed, 15 Mar 2023 22:35:21 +0300
From:   Fedor Pchelkin <pchelkin@ispras.ru>
To:     syzbot+df61b36319e045c00a08@syzkaller.appspotmail.com
Cc:     syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [syzbot] [wireless?] KMSAN: uninit-value in ath9k_hw_init
Message-ID: <20230315193521.jcox7j3is24gk6mj@fpc>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Precedence: bulk

#syz test: https://github.com/google/kmsan.git master

--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -200,20 +200,6 @@ void ath9k_fatal_work(struct work_struct *work)
 	ath9k_htc_reset(priv);
 }
 
-static void ath9k_wmi_rsp_callback(struct wmi *wmi, struct sk_buff *skb)
-{
-	skb_pull(skb, sizeof(struct wmi_cmd_hdr));
-
-	/* Once again validate the SKB. */
-	if (unlikely(skb->len < wmi->cmd_rsp_len))
-		return;
-
-	if (wmi->cmd_rsp_buf != NULL && wmi->cmd_rsp_len != 0)
-		memcpy(wmi->cmd_rsp_buf, skb->data, wmi->cmd_rsp_len);
-
-	complete(&wmi->cmd_wait);
-}
-
 static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb,
 			      enum htc_endpoint_id epid)
 {
@@ -242,14 +228,26 @@ static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb,
 
 	/* Check if there has been a timeout. */
 	spin_lock_irqsave(&wmi->wmi_lock, flags);
-	if (be16_to_cpu(hdr->seq_no) != wmi->last_seq_id) {
+	if (be16_to_cpu(hdr->seq_no) != wmi->last_seq_id ||
+	    be16_to_cpu(hdr->seq_no) == 0) {
+		spin_unlock_irqrestore(&wmi->wmi_lock, flags);
+		goto free_skb;
+	}
+
+	/* Next, process WMI command response */
+	skb_pull(skb, sizeof(struct wmi_cmd_hdr));
+
+	/* Once again validate the SKB. */
+	if (unlikely(skb->len < wmi->cmd_rsp_len)) {
 		spin_unlock_irqrestore(&wmi->wmi_lock, flags);
 		goto free_skb;
 	}
-	spin_unlock_irqrestore(&wmi->wmi_lock, flags);
 
-	/* WMI command response */
-	ath9k_wmi_rsp_callback(wmi, skb);
+	if (wmi->cmd_rsp_buf != NULL && wmi->cmd_rsp_len != 0)
+		memcpy(wmi->cmd_rsp_buf, skb->data, wmi->cmd_rsp_len);
+
+	complete(&wmi->cmd_wait);
+	spin_unlock_irqrestore(&wmi->wmi_lock, flags);
 
 free_skb:
 	kfree_skb(skb);
@@ -287,7 +285,8 @@ int ath9k_wmi_connect(struct htc_target *htc, struct wmi *wmi,
 
 static int ath9k_wmi_cmd_issue(struct wmi *wmi,
 			       struct sk_buff *skb,
-			       enum wmi_cmd_id cmd, u16 len)
+			       enum wmi_cmd_id cmd, u16 len,
+			       u8 *rsp_buf, u32 rsp_len)
 {
 	struct wmi_cmd_hdr *hdr;
 	unsigned long flags;
@@ -297,6 +296,11 @@ static int ath9k_wmi_cmd_issue(struct wmi *wmi,
 	hdr->seq_no = cpu_to_be16(++wmi->tx_seq_id);
 
 	spin_lock_irqsave(&wmi->wmi_lock, flags);
+
+	/* record the rsp buffer and length */
+	wmi->cmd_rsp_buf = rsp_buf;
+	wmi->cmd_rsp_len = rsp_len;
+
 	wmi->last_seq_id = wmi->tx_seq_id;
 	spin_unlock_irqrestore(&wmi->wmi_lock, flags);
 
@@ -337,11 +341,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 		goto out;
 	}
 
-	/* record the rsp buffer and length */
-	wmi->cmd_rsp_buf = rsp_buf;
-	wmi->cmd_rsp_len = rsp_len;
-
-	ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len);
+	ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len, rsp_buf, rsp_len);
 	if (ret)
 		goto out;
 
--