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From:   <sean.wang@mediatek.com>
To:     <nbd@nbd.name>, <lorenzo.bianconi@redhat.com>
CC:     <sean.wang@mediatek.com>, <Soul.Huang@mediatek.com>,
        <YN.Chen@mediatek.com>, <Leon.Yen@mediatek.com>,
        <Eric-SY.Chang@mediatek.com>, <Deren.Wu@mediatek.com>,
        <km.lin@mediatek.com>, <robin.chiu@mediatek.com>,
        <ch.yeh@mediatek.com>, <posh.sun@mediatek.com>,
        <Eric.Liang@mediatek.com>, <Stella.Chang@mediatek.com>,
        <jemele@google.com>, <yenlinlai@google.com>,
        <linux-wireless@vger.kernel.org>,
        <linux-mediatek@lists.infradead.org>
Subject: [PATCH] mt76: mt7921: fix the coredump is being truncated
Date:   Thu, 17 Jun 2021 09:39:19 +0800
Message-ID: <2ebb95099102ffe62c0fa8aedd95d7e77b5ca385.1623884856.git.objelf@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

From: Sean Wang <sean.wang@mediatek.com>

Fix the maximum size of the coredump generated with current mt7921
firmware. Otherwise, a truncated coredump would be reported to userland
via dev_coredumpv.

Also, there is an additional error handling enhanced in the patch to avoid
the possible invalid buffer access when the system failed to create the
buffer to hold the coredump.

Fixes: 0da3c795d07b ("mt76: mt7921: add coredump support")
Co-developed-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
 drivers/net/wireless/mediatek/mt76/mt76_connac.h | 2 +-
 drivers/net/wireless/mediatek/mt76/mt7921/mac.c  | 9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac.h b/drivers/net/wireless/mediatek/mt76/mt76_connac.h
index 9b3f8d22f17e..d93ab1ece8ae 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76_connac.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76_connac.h
@@ -13,7 +13,7 @@
 #define MT76_CONNAC_MAX_SCAN_MATCH		16
 
 #define MT76_CONNAC_COREDUMP_TIMEOUT		(HZ / 20)
-#define MT76_CONNAC_COREDUMP_SZ			(128 * 1024)
+#define MT76_CONNAC_COREDUMP_SZ			(1300 * 1024)
 
 enum {
 	CMD_CBW_20MHZ = IEEE80211_STA_RX_BW_20,
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index fb4de73df701..905dddbfbb0b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -1557,7 +1557,7 @@ void mt7921_coredump_work(struct work_struct *work)
 			break;
 
 		skb_pull(skb, sizeof(struct mt7921_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;
 		}
@@ -1567,7 +1567,10 @@ void mt7921_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);
+
 	mt7921_reset(&dev->mt76);
 }
-- 
2.25.1