Re: [PATCH] gpib: fmh_gpib: Fix resource leaks in fmh_gpib_attach_impl

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, May 27, 2026 at 05:54:50PM +0800, Hongling Zeng wrote:
> The fmh_gpib_attach_impl() function has multiple resource leaks in its
> error handling paths. When any initialization step fails, the function
> returns early without properly releasing previously acquired resources.
> 
> Fix by adding proper error handling labels and cleanup code that releases
> resources in the reverse order they were acquired.
> 
> Fixes: 8e4841a0888c7 ("staging: gpib: Add Frank Mori Hess FPGA PCI GPIB driver")
> Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
> ---
>  drivers/gpib/fmh_gpib/fmh_gpib.c | 46 ++++++++++++++++++++++++--------
>  1 file changed, 35 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpib/fmh_gpib/fmh_gpib.c b/drivers/gpib/fmh_gpib/fmh_gpib.c
> index fcafdc02ea2e..af582453fef7 100644
> --- a/drivers/gpib/fmh_gpib/fmh_gpib.c
> +++ b/drivers/gpib/fmh_gpib/fmh_gpib.c
> @@ -1403,14 +1403,17 @@ static int fmh_gpib_attach_impl(struct gpib_board *board, const struct gpib_boar
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gpib_control_status");
>  	if (!res) {
>  		dev_err(board->dev, "Unable to locate mmio resource\n");
> -		return -ENODEV;
> +		retval = -ENODEV;
> +		return retval;
>  	}
>  
>  	if (request_mem_region(res->start,
>  			       resource_size(res),
>  			       pdev->name) == NULL) {
>  		dev_err(board->dev, "cannot claim registers\n");
> -		return -ENXIO;
> +		retval = -ENXIO;
> +		return retval;
> +
>  	}
>  	e_priv->gpib_iomem_res = res;
>  
> @@ -1418,7 +1421,8 @@ static int fmh_gpib_attach_impl(struct gpib_board *board, const struct gpib_boar
>  				     resource_size(e_priv->gpib_iomem_res));
>  	if (!nec_priv->mmiobase) {
>  		dev_err(board->dev, "Could not map I/O memory\n");
> -		return -ENOMEM;
> +		retval = -ENOMEM;
> +		goto err_release_gpib_region;
>  	}
>  	dev_dbg(board->dev, "iobase %pr remapped to %p\n",
>  		e_priv->gpib_iomem_res, nec_priv->mmiobase);
> @@ -1426,42 +1430,48 @@ static int fmh_gpib_attach_impl(struct gpib_board *board, const struct gpib_boar
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dma_fifos");
>  	if (!res) {
>  		dev_err(board->dev, "Unable to locate mmio resource for gpib dma port\n");
> -		return -ENODEV;
> +		retval = -ENODEV;
> +		goto err_iounmap_gpib;
>  	}
>  	if (request_mem_region(res->start,
>  			       resource_size(res),
>  			       pdev->name) == NULL) {
>  		dev_err(board->dev, "cannot claim registers\n");
> -		return -ENXIO;
> +		retval = -ENXIO;
> +		goto err_iounmap_gpib;
>  	}
>  	e_priv->dma_port_res = res;
>  	e_priv->fifo_base = ioremap(e_priv->dma_port_res->start,
>  				    resource_size(e_priv->dma_port_res));
>  	if (!e_priv->fifo_base) {
>  		dev_err(board->dev, "Could not map I/O memory for fifos\n");
> -		return -ENOMEM;
> +		retval = -ENOMEM;
> +		goto err_release_dma_region;
>  	}
>  	dev_dbg(board->dev, "dma fifos 0x%lx remapped to %p, length=%ld\n",
>  		(unsigned long)e_priv->dma_port_res->start, e_priv->fifo_base,
>  		(unsigned long)resource_size(e_priv->dma_port_res));
>  
>  	irq = platform_get_irq(pdev, 0);
> -	if (irq < 0)
> -		return -EBUSY;
> +	if (irq < 0) {
> +		retval = -EBUSY;
> +		goto err_iounmap_fifo;
> +	}
> +	e_priv->irq = irq;
>  	retval = request_irq(irq, fmh_gpib_interrupt, IRQF_SHARED, pdev->name, board);
>  	if (retval) {
>  		dev_err(board->dev,
>  			"cannot register interrupt handler err=%d\n",
>  			retval);
> -		return retval;
> +		goto err_iounmap_fifo;
>  	}
> -	e_priv->irq = irq;
>  
>  	if (acquire_dma) {
>  		e_priv->dma_channel = dma_request_slave_channel(board->dev, "rxtx");
>  		if (!e_priv->dma_channel) {
>  			dev_err(board->dev, "failed to acquire dma channel \"rxtx\".\n");
> -			return -EIO;
> +			retval = -EIO;
> +			goto err_free_irq;
>  		}
>  	}
>  	/*
> @@ -1473,6 +1483,20 @@ static int fmh_gpib_attach_impl(struct gpib_board *board, const struct gpib_boar
>  		fifo_max_burst_length_mask;
>  
>  	return fmh_gpib_init(e_priv, board, handshake_mode);
> +
> +err_free_irq:
> +	free_irq(e_priv->irq, board);
> +err_iounmap_fifo:
> +	iounmap(e_priv->fifo_base);
> +err_release_dma_region:
> +	release_mem_region(e_priv->dma_port_res->start,
> +				resource_size(e_priv->dma_port_res));
> +err_iounmap_gpib:
> +	iounmap(nec_priv->mmiobase);
> +err_release_gpib_region:
> +	release_mem_region(e_priv->gpib_iomem_res->start,
> +				resource_size(e_priv->gpib_iomem_res));
> +	return retval;
>  }
>  
>  int fmh_gpib_attach_holdoff_all(struct gpib_board *board, const struct gpib_board_config *config)
> -- 
> 2.25.1
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- You have marked a patch with a "Fixes:" tag for a commit that is in an
  older released kernel, yet you do not have a cc: stable line in the
  signed-off-by area at all, which means that the patch will not be
  applied to any older kernel releases.  To properly fix this, please
  follow the documented rules in the
  Documentation/process/stable-kernel-rules.rst file for how to resolve
  this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot