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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Felix Fietkau <nbd@nbd.name>
Subject: [PATCH 5.10 057/530] mt76: fix potential DMA mapping leak
Date:   Wed, 12 May 2021 16:42:47 +0200
Message-Id: <20210512144821.605251052@linuxfoundation.org>
In-Reply-To: <20210512144819.664462530@linuxfoundation.org>
References: <20210512144819.664462530@linuxfoundation.org>
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From: Felix Fietkau <nbd@nbd.name>

commit b4403cee6400c5f679e9c4a82b91d61aa961eccf upstream.

With buf uninitialized in mt76_dma_tx_queue_skb_raw, its field skip_unmap
could potentially inherit a non-zero value from stack garbage.
If this happens, it will cause DMA mappings for MCU command frames to not be
unmapped after completion

Fixes: 27d5c528a7ca ("mt76: fix double DMA unmap of the first buffer on 7615/7915")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireless/mediatek/mt76/dma.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -318,7 +318,7 @@ mt76_dma_tx_queue_skb_raw(struct mt76_de
 			  struct sk_buff *skb, u32 tx_info)
 {
 	struct mt76_queue *q = dev->q_tx[qid];
-	struct mt76_queue_buf buf;
+	struct mt76_queue_buf buf = {};
 	dma_addr_t addr;
 
 	if (q->queued + 1 >= q->ndesc - 1)