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

[Hongling Zeng <zhongling0719@126.com>]

   Hi Dominik,

   Thank you for the review. You're right on all three points:

在 2026年05月27日 21:14, Dominik Karol Piątkowski 写道:
> Hi Hongling Zeng,
>
> On Wednesday, May 27th, 2026 at 11:55, Hongling Zeng <zenghongling@kylinos.cn> 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;
> Replacing `return -errno` with `retval = -errno` just to have `return retval`
> directly under it does not convince me.
Early error returns can just use return -ENODEV directly
>>   	}
>>
>>   	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;
>> +
> Same here, also introducing unnecessary newline.
Will remove the extra newline
>
>>   	}
>>   	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;
> I don't think this assignment should be moved before request_irq.
>
> Thanks,
> Dominik Karol
e_priv->irq = irq; should stay after request_irq() succeeds - my concern 
about uninitialized values in error paths was incorrect since 
err_iounmap_fifo doesn't use e_priv->irq

   I'll fix these issues and resubmit.

   Best regards,
   Hongling Zeng

>>   	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
>>
>>