[PATCH] dma-buf: call kfree() w/o mutex held in dma_buf_attach()

[PATCH] dma-buf: call kfree() w/o mutex held in dma_buf_attach()

[Emil Velikov]

From: Emil Velikov <emil.velikov@collabora.com>

In dma_buf_attach() we allocate memory w/o a mutex being held, thus in
the error path we should kfree() it after the mutex_unlock.

The inverse function dma_buf_deattach() gets this right.

Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
---
 drivers/dma-buf/dma-buf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 3ae6c0c2cc02..57ddeb735b8b 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -579,8 +579,8 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 	return attach;
 
 err_attach:
-	kfree(attach);
 	mutex_unlock(&dmabuf->lock);
+	kfree(attach);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dma_buf_attach);
-- 
2.21.0

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Re: [PATCH] dma-buf: call kfree() w/o mutex held in dma_buf_attach()

[Daniel Vetter]

On Thu, Apr 25, 2019 at 04:48:50PM +0100, Emil Velikov wrote:
> From: Emil Velikov <emil.velikov@collabora.com>
> 
> In dma_buf_attach() we allocate memory w/o a mutex being held, thus in
> the error path we should kfree() it after the mutex_unlock.
> 
> The inverse function dma_buf_deattach() gets this right.
> 
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

I don't think this matters, but +1 on ocd.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/dma-buf/dma-buf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 3ae6c0c2cc02..57ddeb735b8b 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -579,8 +579,8 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
>  	return attach;
>  
>  err_attach:
> -	kfree(attach);
>  	mutex_unlock(&dmabuf->lock);
> +	kfree(attach);
>  	return ERR_PTR(ret);
>  }
>  EXPORT_SYMBOL_GPL(dma_buf_attach);
> -- 
> 2.21.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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