Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v5] tty: 8250: fix a missing check for pci_ioremap_bar
To:     Aditya Pakki <pakki001@umn.edu>
Cc:     Vinod Koul <vkoul@kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>, kjlu@umn.edu,
        linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org
References: <20190324192209.27202-1-pakki001@umn.edu>
From:   Jiri Slaby <jslaby@suse.cz>
Openpgp: preference=signencrypt
Autocrypt: addr=jslaby@suse.cz; prefer-encrypt=mutual; keydata=
 mQINBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j
 rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk
 rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ
 i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx
 wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx
 ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H
 cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL
 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps
 w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm
 YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABtBtKaXJpIFNsYWJ5
 IDxqc2xhYnlAc3VzZS5jej6JAjgEEwECACIFAk6S6NgCGwMGCwkIBwMCBhUIAgkKCwQWAgMB
 Ah4BAheAAAoJEL0lsQQGtHBJgDsP/j9wh0vzWXsOPO3rDpHjeC3BT5DKwjVN/KtP7uZttlkB
 duReCYMTZGzSrmK27QhCflZ7Tw0Naq4FtmQSH8dkqVFugirhlCOGSnDYiZAAubjTrNLTqf7e
 5poQxE8mmniH/Asg4KufD9bpxSIi7gYIzaY3hqvYbVF1vYwaMTujojlixvesf0AFlE4x8WKs
 wpk43fmo0ZLcwObTnC3Hl1JBsPujCVY8t4E7zmLm7kOB+8EHaHiRZ4fFDWweuTzRDIJtVmrH
 LWvRDAYg+IH3SoxtdJe28xD9KoJw4jOX1URuzIU6dklQAnsKVqxz/rpp1+UVV6Ky6OBEFuoR
 613qxHCFuPbkRdpKmHyE0UzmniJgMif3v0zm/+1A/VIxpyN74cgwxjhxhj/XZWN/LnFuER1W
 zTHcwaQNjq/I62AiPec5KgxtDeV+VllpKmFOtJ194nm9QM9oDSRBMzrG/2AY/6GgOdZ0+qe+
 4BpXyt8TmqkWHIsVpE7I5zVDgKE/YTyhDuqYUaWMoI19bUlBBUQfdgdgSKRMJX4vE72dl8BZ
 +/ONKWECTQ0hYntShkmdczcUEsWjtIwZvFOqgGDbev46skyakWyod6vSbOJtEHmEq04NegUD
 al3W7Y/FKSO8NqcfrsRNFWHZ3bZ2Q5X0tR6fc6gnZkNEtOm5fcWLY+NVz4HLaKrJuQINBE6S
 54YBEADPnA1iy/lr3PXC4QNjl2f4DJruzW2Co37YdVMjrgXeXpiDvneEXxTNNlxUyLeDMcIQ
 K8obCkEHAOIkDZXZG8nr4mKzyloy040V0+XA9paVs6/ice5l+yJ1eSTs9UKvj/pyVmCAY1Co
 SNN7sfPaefAmIpduGacp9heXF+1Pop2PJSSAcCzwZ3PWdAJ/w1Z1Dg/tMCHGFZ2QCg4iFzg5
 Bqk4N34WcG24vigIbRzxTNnxsNlU1H+tiB81fngUp2pszzgXNV7CWCkaNxRzXi7kvH+MFHu2
 1m/TuujzxSv0ZHqjV+mpJBQX/VX62da0xCgMidrqn9RCNaJWJxDZOPtNCAWvgWrxkPFFvXRl
 t52z637jleVFL257EkMI+u6UnawUKopa+Tf+R/c+1Qg0NHYbiTbbw0pU39olBQaoJN7JpZ99
 T1GIlT6zD9FeI2tIvarTv0wdNa0308l00bas+d6juXRrGIpYiTuWlJofLMFaaLYCuP+e4d8x
 rGlzvTxoJ5wHanilSE2hUy2NSEoPj7W+CqJYojo6wTJkFEiVbZFFzKwjAnrjwxh6O9/V3O+Z
 XB5RrjN8hAf/4bSo8qa2y3i39cuMT8k3nhec4P9M7UWTSmYnIBJsclDQRx5wSh0Mc9Y/psx9
 B42WbV4xrtiiydfBtO6tH6c9mT5Ng+d1sN/VTSPyfQARAQABiQIfBBgBAgAJBQJOkueGAhsM
 AAoJEL0lsQQGtHBJN7UQAIDvgxaW8iGuEZZ36XFtewH56WYvVUefs6+Pep9ox/9ZXcETv0vk
 DUgPKnQAajG/ViOATWqADYHINAEuNvTKtLWmlipAI5JBgE+5g9UOT4i69OmP/is3a/dHlFZ3
 qjNk1EEGyvioeycJhla0RjakKw5PoETbypxsBTXk5EyrSdD/I2Hez9YGW/RcI/WC8Y4Z/7FS
 ITZhASwaCOzy/vX2yC6iTx4AMFt+a6Z6uH/xGE8pG5NbGtd02r+m7SfuEDoG3Hs1iMGecPyV
 XxCVvSV6dwRQFc0UOZ1a6ywwCWfGOYqFnJvfSbUiCMV8bfRSWhnNQYLIuSv/nckyi8CzCYIg
 c21cfBvnwiSfWLZTTj1oWyj5a0PPgGOdgGoIvVjYXul3yXYeYOqbYjiC5t99JpEeIFupxIGV
 ciMk6t3pDrq7n7Vi/faqT+c4vnjazJi0UMfYnnAzYBa9+NkfW0w5W9Uy7kW/v7SffH/2yFiK
 9HKkJqkN9xYEYaxtfl5pelF8idoxMZpTvCZY7jhnl2IemZCBMs6s338wS12Qro5WEAxV6cjD
 VSdmcD5l9plhKGLmgVNCTe8DPv81oDn9s0cIRLg9wNnDtj8aIiH8lBHwfUkpn32iv0uMV6Ae
 sLxhDWfOR4N+wu1gzXWgLel4drkCJcuYK5IL1qaZDcuGR8RPo3jbFO7Y
Message-ID: <6d82a501-59f7-67e7-85fd-8fe44e7793d3@suse.cz>
Date:   Mon, 25 Mar 2019 07:25:38 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.5.2
MIME-Version: 1.0
In-Reply-To: <20190324192209.27202-1-pakki001@umn.edu>
Content-Type: text/plain; charset=iso-8859-2
Content-Language: en-GB
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 24. 03. 19, 20:22, Aditya Pakki wrote:
> pci_ioremap_bar could fail. The patch returns in case of failure to
> acquire IOMEM. It also releases the acquired resource in the exit path.
> 
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> 
> ---
> v4: Missed resource release in dma_probe failure.
> v3: Change the order of pci_iounmap and dw_dma_remove
> v2: Failed to release resource in exit path and incorrect code in non
> DMA case, suggested by Andy Shevchenko
> v1: Missed return by default in CONFIG_SERIAL_8250_DMA, suggested by
> Jiri Slaby
> ---
>  drivers/tty/serial/8250/8250_lpss.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
> index 53ca9ba6ab4b..a098902221df 100644
> --- a/drivers/tty/serial/8250/8250_lpss.c
> +++ b/drivers/tty/serial/8250/8250_lpss.c
> @@ -170,14 +170,18 @@ static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
>  	int ret;
>  
>  	chip->dev = &pdev->dev;
> +	chip->pdata = &qrk_serial_dma_pdata;
>  	chip->irq = pci_irq_vector(pdev, 0);
>  	chip->regs = pci_ioremap_bar(pdev, 1);
> -	chip->pdata = &qrk_serial_dma_pdata;
> +	if (!chip->regs)
> +		return;
>  
>  	/* Falling back to PIO mode if DMA probing fails */
>  	ret = dw_dma_probe(chip);
> -	if (ret)
> +	if (ret) {
> +		pci_iounmap(pdev, chip->regs);
>  		return;
> +	}
>  
>  	pci_try_set_mwi(pdev);
>  
> @@ -199,7 +203,10 @@ static void qrk_serial_exit_dma(struct lpss8250 *lpss)
>  
>  	if (!param->dma_dev)
>  		return;
> +
>  	dw_dma_remove(&lpss->dma_chip);
> +
> +	pci_iounmap(param->dma_dev, &lpss->dma_chip->regs);

pci_iounmap is a counterpart of pci_iomap, not pci_ioremap_bar.

You should use plain iounmap. pci_iounmap should do the right job on x86
at least too. But I am not so sure about the other archs -- I suspect
s390 to emit a WARNING.

>  }
>  #else	/* CONFIG_SERIAL_8250_DMA */
>  static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
> 

thanks,
-- 
js
suse labs