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Groups > linux.kernel > #1343566 > unrolled thread

[PATCH][V2] mt7601u: do not free dma_buf when ivp allocation fails

Started byColin King <colin.king@canonical.com>
First post2016-02-26 00:20 +0100
Last post2016-02-26 00:20 +0100
Articles 2 — 2 participants

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  [PATCH][V2] mt7601u: do not free dma_buf when ivp allocation fails Colin King <colin.king@canonical.com> - 2016-02-26 00:20 +0100
    Re: [PATCH][V2] mt7601u: do not free dma_buf when ivp allocation fails Julian Calaby <julian.calaby@gmail.com> - 2016-02-26 00:20 +0100

#1343566 — [PATCH][V2] mt7601u: do not free dma_buf when ivp allocation fails

FromColin King <colin.king@canonical.com>
Date2016-02-26 00:20 +0100
Subject[PATCH][V2] mt7601u: do not free dma_buf when ivp allocation fails
Message-ID<r6dmp-2FR-1@gated-at.bofh.it>
From: Colin Ian King <colin.king@canonical.com>

If the allocation of ivp fails the error handling attempts to
free an uninitialized dma_buf; this data structure just contains
garbage on the stack, so the freeing will cause issues when the
urb, buf and dma fields are free'd. Fix this by not free'ing the
dma_buf if the ivp allocation fails.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/wireless/mediatek/mt7601u/mcu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt7601u/mcu.c b/drivers/net/wireless/mediatek/mt7601u/mcu.c
index fbb1986..70e4b5e 100644
--- a/drivers/net/wireless/mediatek/mt7601u/mcu.c
+++ b/drivers/net/wireless/mediatek/mt7601u/mcu.c
@@ -362,10 +362,10 @@ mt7601u_upload_firmware(struct mt7601u_dev *dev, const struct mt76_fw *fw)
 	int i, ret;
 
 	ivb = kmemdup(fw->ivb, sizeof(fw->ivb), GFP_KERNEL);
-	if (!ivb || mt7601u_usb_alloc_buf(dev, MCU_FW_URB_SIZE, &dma_buf)) {
-		ret = -ENOMEM;
+	if (!ivb)
+		return -ENOMEM;
+	if (mt7601u_usb_alloc_buf(dev, MCU_FW_URB_SIZE, &dma_buf))
 		goto error;
-	}
 
 	ilm_len = le32_to_cpu(fw->hdr.ilm_len) - sizeof(fw->ivb);
 	dev_dbg(dev->dev, "loading FW - ILM %u + IVB %zu\n",
-- 
2.7.0

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#1343567

FromJulian Calaby <julian.calaby@gmail.com>
Date2016-02-26 00:20 +0100
Message-ID<r6dmp-2FR-3@gated-at.bofh.it>
In reply to#1343566
Hi Colin,

On Fri, Feb 26, 2016 at 10:09 AM, Colin King <colin.king@canonical.com> wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> If the allocation of ivp fails the error handling attempts to
> free an uninitialized dma_buf; this data structure just contains
> garbage on the stack, so the freeing will cause issues when the
> urb, buf and dma fields are free'd. Fix this by not free'ing the
> dma_buf if the ivp allocation fails.
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/net/wireless/mediatek/mt7601u/mcu.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt7601u/mcu.c b/drivers/net/wireless/mediatek/mt7601u/mcu.c
> index fbb1986..70e4b5e 100644
> --- a/drivers/net/wireless/mediatek/mt7601u/mcu.c
> +++ b/drivers/net/wireless/mediatek/mt7601u/mcu.c
> @@ -362,10 +362,10 @@ mt7601u_upload_firmware(struct mt7601u_dev *dev, const struct mt76_fw *fw)
>         int i, ret;
>
>         ivb = kmemdup(fw->ivb, sizeof(fw->ivb), GFP_KERNEL);
> -       if (!ivb || mt7601u_usb_alloc_buf(dev, MCU_FW_URB_SIZE, &dma_buf)) {
> -               ret = -ENOMEM;
> +       if (!ivb)
> +               return -ENOMEM;
> +       if (mt7601u_usb_alloc_buf(dev, MCU_FW_URB_SIZE, &dma_buf))
>                 goto error;

Are you sure this is right? Isn't ret unset here and consequently
returned at the end of the error label?

Thanks,

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/

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