[PATCH 3/3] wifi: ath9k: fix ath9k_wmi_cmd return value when device is unplugged

[Fedor Pchelkin]

Return with an error code in case the USB device has been already
unplugged. Otherwise the callers of ath9k_wmi_cmd() are unaware of the
fact that cmd_buf and rsp_buf are not initialized or handled properly
inside this function.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: a3be14b76da1 ("ath9k_htc: Handle device unplug properly")
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
---
 drivers/net/wireless/ath/ath9k/wmi.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c
index 99a91bbaace9..3e0ad4f8f0a0 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -320,8 +320,11 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 	unsigned long time_left;
 	int ret = 0;
 
-	if (ah->ah_flags & AH_UNPLUGGED)
-		return 0;
+	if (ah->ah_flags & AH_UNPLUGGED) {
+		ath_dbg(common, WMI, "Device unplugged for WMI command: %s\n",
+			wmi_cmd_to_name(cmd_id));
+		return -ENODEV;
+	}
 
 	skb = alloc_skb(headroom + cmd_len, GFP_ATOMIC);
 	if (!skb)
-- 
2.34.1