Re: [PATCH] platform/x86: dell_rbu: fix lock imbalance in img_update_realloc

[Stuart Hayes]

On 2/11/2019 7:09 AM, Christoph Hellwig wrote:
> We need to ensure rbu_data.lock is always held on return.
> 
> Fixes: 289790a3ea94 ("platform/x86: dell_rbu: stop abusing the DMA API")
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  drivers/platform/x86/dell_rbu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/dell_rbu.c b/drivers/platform/x86/dell_rbu.c
> index 8104ca0c44ca..031c68903583 100644
> --- a/drivers/platform/x86/dell_rbu.c
> +++ b/drivers/platform/x86/dell_rbu.c
> @@ -436,6 +436,7 @@ static int img_update_realloc(unsigned long size)
>  	ordernum = get_order(size);
>  	image_update_buffer =
>  		(unsigned char *)__get_free_pages(GFP_DMA32, ordernum);
> +	spin_lock(&rbu_data.lock);
>  	if (!image_update_buffer) {
>  		pr_debug("Not enough memory for image update:"
>  			"size = %ld\n", size);
> @@ -446,7 +447,6 @@ static int img_update_realloc(unsigned long size)
>  	if (WARN_ON_ONCE(img_buf_phys_addr > BIOS_SCAN_LIMIT))
>  		return -EINVAL; /* can't happen per definition */
>  
> -	spin_lock(&rbu_data.lock);
>  	rbu_data.image_update_buffer = image_update_buffer;
>  	rbu_data.image_update_buffer_size = size;
>  	rbu_data.bios_image_size = rbu_data.image_update_buffer_size;
> 

Acked-by: Stuart Hayes <stuart.w.hayes@xxxxxxxxx>