2019-03-24 16:11:39

by Aditya Pakki

Subject: [PATCH v3] 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]>

---
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 | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index 53ca9ba6ab4b..7889b2552013 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -170,9 +170,11 @@ 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);
@@ -199,6 +201,7 @@ static void qrk_serial_exit_dma(struct lpss8250 *lpss)

if (!param->dma_dev)
return;
+ pci_iounmap(param->dma_dev, &lpss->dma_chip->regs);
dw_dma_remove(&lpss->dma_chip);
}
#else /* CONFIG_SERIAL_8250_DMA */
--
2.17.1

2019-03-24 16:31:23

by Andy Shevchenko

Subject: Re: [PATCH v3] tty: 8250: fix a missing check for pci_ioremap_bar

On Sun, Mar 24, 2019 at 11:09:00AM -0500, 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.

Thanks for an update.
Almost, but one think below.

>
> Signed-off-by: Aditya Pakki <[email protected]>
>
> ---
> 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 | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
> index 53ca9ba6ab4b..7889b2552013 100644
> --- a/drivers/tty/serial/8250/8250_lpss.c
> +++ b/drivers/tty/serial/8250/8250_lpss.c
> @@ -170,9 +170,11 @@ 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);
> @@ -199,6 +201,7 @@ static void qrk_serial_exit_dma(struct lpss8250 *lpss)
>
> if (!param->dma_dev)
> return;

> + pci_iounmap(param->dma_dev, &lpss->dma_chip->regs);

This will fail the DMA driver ->remove() badly.
You need to do this after removal of DMA itself.
See the symmetry with setup above?

> dw_dma_remove(&lpss->dma_chip);

...put it here.
Don't forget to separate from above with blank line.

--
With Best Regards,
Andy Shevchenko