linux-kernel - Re: [PATCH v2 3/7] dmaengine: idxd: fix memory leak in error handling path of idxd_setup

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Message-ID: <693fe8b5-ff99-4363-8c9d-9641ad24ba10@nvidia.com>
Date: Tue, 18 Feb 2025 12:20:06 -0800
From: Fenghua Yu <fenghuay@...dia.com>
To: Shuai Xue <xueshuai@...ux.alibaba.com>, vinicius.gomes@...el.com,
 dave.jiang@...el.com, vkoul@...nel.org
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/7] dmaengine: idxd: fix memory leak in error handling
 path of idxd_setup_groups

Hi, Shuai,

On 2/14/25 21:44, Shuai Xue wrote:
> Memory allocated for groups is not freed if an error occurs during
> idxd_setup_groups(). To fix it, free the allocated memory in the reverse
> order of allocation before exiting the function in case of an error.
>
> Fixes: defe49f96012 ("dmaengine: idxd: fix group conf_dev lifetime")
> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
> Reviewed-by: Dave Jiang <dave.jiang@...el.com>
> ---
>   drivers/dma/idxd/init.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index 4e47075c5bef..a2da68e6144d 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -328,6 +328,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   		rc = dev_set_name(conf_dev, "group%d.%d", idxd->id, group->id);
>   		if (rc < 0) {
>   			put_device(conf_dev);
> +			kfree(group);
>   			goto err;
>   		}
>   
> @@ -352,7 +353,10 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   	while (--i >= 0) {
>   		group = idxd->groups[i];
>   		put_device(group_confdev(group));
> +		kfree(group);
>   	}
> +	kfree(idxd->groups);
> +

What happens to the memory areas previously allocated for wqs and 
engines after idxd_setup_groups() fails? They need to be freed as well, 
but currently they are not.

Maybe a separate patch cleans up the previously allocated mem areas for 
wqs/engines/groups if there is any failure after the allocations?



>   	return rc;
>   }
>   

Thanks.


-Fenghua