[PATCH v3] wifi: mt76: handle failure of vzalloc in mt7615_coredump_work

[void0red]

From: Kang Chen <void0red at gmail.com>

vzalloc may fails, dump might be null and will cause
illegal address access later.

Link: https://lore.kernel.org/all/Y%2Fy5Asxw3T3m4jCw@lore-desk
Fixes: d2bf7959d9c0 ("mt76: mt7663: introduce coredump support")
Signed-off-by: Kang Chen <void0red at gmail.com>
---
v3 -> v2: fix bugs
v2 -> v1: add Fixes tag

 drivers/net/wireless/mediatek/mt76/mt7615/mac.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index a95602473..796768011 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -2380,7 +2380,7 @@ void mt7615_coredump_work(struct work_struct *work)
 			break;
 
 		skb_pull(skb, sizeof(struct mt7615_mcu_rxd));
-		if (data + skb->len - dump > MT76_CONNAC_COREDUMP_SZ) {
+		if (!dump || data + skb->len - dump > MT76_CONNAC_COREDUMP_SZ) {
 			dev_kfree_skb(skb);
 			continue;
 		}
@@ -2390,6 +2390,8 @@ void mt7615_coredump_work(struct work_struct *work)
 
 		dev_kfree_skb(skb);
 	}
-	dev_coredumpv(dev->mt76.dev, dump, MT76_CONNAC_COREDUMP_SZ,
-		      GFP_KERNEL);
+
+	if (dump)
+		dev_coredumpv(dev->mt76.dev, dump, MT76_CONNAC_COREDUMP_SZ,
+			      GFP_KERNEL);
 }
-- 
2.34.1