2019-03-24 19:23:06

by Aditya Pakki

Subject: [PATCH v5] tty: 8250: fix a missing check for pci_ioremap_bar

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 <[email protected]>

---
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);
}
#else /* CONFIG_SERIAL_8250_DMA */
static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
--
2.17.1

2019-03-25 06:28:12

by Jiri Slaby

Subject: Re: [PATCH v5] tty: 8250: fix a missing check for pci_ioremap_bar

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 <[email protected]>
>
> ---
> 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