[PATCH] pci: pcie-rcar: fix a potential NULL pointer dereference

[PATCH] pci: pcie-rcar: fix a potential NULL pointer dereference

[Kangjie Lu]

In case __get_free_pages fails and returns NULL, the fix returns
-ENOMEM and releases resources to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/pci/controller/pcie-rcar.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index c8febb009454..0ba26c31d928 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -929,6 +929,12 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
 
 	/* setup MSI data target */
 	msi->pages = __get_free_pages(GFP_KERNEL, 0);
+	if (!msi->pages) {
+		dev_err(dev, "failed to get free pages\n");
+		err = -ENOMEM;
+		goto err;
+	}
+
 	base = virt_to_phys((void *)msi->pages);
 
 	rcar_pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
-- 
2.17.1

Re: [PATCH] pci: pcie-rcar: fix a potential NULL pointer dereference

[Geert Uytterhoeven]

Hi Kangjie,

On Thu, Mar 14, 2019 at 6:56 AM Kangjie Lu <kjlu@umn.edu> wrote:
> In case __get_free_pages fails and returns NULL, the fix returns
> -ENOMEM and releases resources to avoid NULL pointer dereference.
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>

Thanks for your patch!

> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -929,6 +929,12 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
>
>         /* setup MSI data target */
>         msi->pages = __get_free_pages(GFP_KERNEL, 0);
> +       if (!msi->pages) {
> +               dev_err(dev, "failed to get free pages\n");

Please drop the dev_err().
The memory allocation core will already have printed a warning, cfr.
warn_alloc() in mm/page_alloc.c.

With that fixed:
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> +               err = -ENOMEM;
> +               goto err;
> +       }
> +

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2] pci: pcie-rcar: fix a potential NULL pointer dereference

[Kangjie Lu]

In case __get_free_pages fails and returns NULL, the fix returns
-ENOMEM and releases resources to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>

---
V2 removes the error message.
---
 drivers/pci/controller/pcie-rcar.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index c8febb009454..71e55995c058 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -929,6 +929,10 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
 
 	/* setup MSI data target */
 	msi->pages = __get_free_pages(GFP_KERNEL, 0);
+	if (!msi->pages) {
+		err = -ENOMEM;
+		goto err;
+	}
 	base = virt_to_phys((void *)msi->pages);
 
 	rcar_pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
-- 
2.17.1

Re: [PATCH v2] pci: pcie-rcar: fix a potential NULL pointer dereference

[Geert Uytterhoeven]

On Thu, Mar 14, 2019 at 9:08 AM Kangjie Lu <kjlu@umn.edu> wrote:
> In case __get_free_pages fails and returns NULL, the fix returns
> -ENOMEM and releases resources to avoid NULL pointer dereference.
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>

Please keep my
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2] tty: atmel_serial: fix a NULL pointer dereference

[Kangjie Lu]

Fixes: 34df42f59a60 ("serial: at91: add rx dma support")

In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>

---
V2: simplified the patch as suggested by
Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/atmel_serial.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..41b728d223d1 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
-- 
2.17.1

Re: [PATCH v2] tty: atmel_serial: fix a NULL pointer dereference

[Richard Genoud]

Le 15/03/2019 à 08:27, Kangjie Lu a écrit :
> Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
The Fixes: tag should be just bellow the Signenf-off-by: tag
> 
> In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
> error code to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
^^^
here
> 
> ---
> V2: simplified the patch as suggested by
> Richard Genoud <richard.genoud@gmail.com>
> ---
>  drivers/tty/serial/atmel_serial.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 05147fe24343..41b728d223d1 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  					 sg_dma_len(&atmel_port->sg_rx)/2,
>  					 DMA_DEV_TO_MEM,
>  					 DMA_PREP_INTERRUPT);
> +	if (!desc) {
> +		dev_err(port->dev, "Preparing DMA cyclic failed\n");
> +		goto chan_err;
> +	}
>  	desc->callback = atmel_complete_rx_dma;
>  	desc->callback_param = port;
>  	atmel_port->desc_rx = desc;
> 

Thanks !

Richard.

[PATCH] tty: atmel_serial: fix a NULL pointer dereference

[Kangjie Lu]

In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Fixes: 34df42f59a60 ("serial: at91: add rx dma support")

---
V2: simplified the patch as suggested by
Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/atmel_serial.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..41b728d223d1 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
-- 
2.17.1

Re: [PATCH] tty: atmel_serial: fix a NULL pointer dereference

[Richard Genoud]

Le 15/03/2019 à 18:16, Kangjie Lu a écrit :
> In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
> error code to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
Acked-by: Richard Genoud <richard.genoud@gmail.com>

> 
> ---
> V2: simplified the patch as suggested by
> Richard Genoud <richard.genoud@gmail.com>
> ---
>  drivers/tty/serial/atmel_serial.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 05147fe24343..41b728d223d1 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  					 sg_dma_len(&atmel_port->sg_rx)/2,
>  					 DMA_DEV_TO_MEM,
>  					 DMA_PREP_INTERRUPT);
> +	if (!desc) {
> +		dev_err(port->dev, "Preparing DMA cyclic failed\n");
> +		goto chan_err;
> +	}
>  	desc->callback = atmel_complete_rx_dma;
>  	desc->callback_param = port;
>  	atmel_port->desc_rx = desc;
> 

Thanks !

Richard

[PATCH v2] pci: pcie-rcar: fix a potential NULL pointer dereference

[Kangjie Lu]

In case __get_free_pages fails and returns NULL, the fix returns
-ENOMEM and releases resources to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

---
V2 removes the error message.
---
 drivers/pci/controller/pcie-rcar.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index c8febb009454..71e55995c058 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -929,6 +929,10 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
 
 	/* setup MSI data target */
 	msi->pages = __get_free_pages(GFP_KERNEL, 0);
+	if (!msi->pages) {
+		err = -ENOMEM;
+		goto err;
+	}
 	base = virt_to_phys((void *)msi->pages);
 
 	rcar_pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
-- 
2.17.1

Re: [PATCH v2] pci: pcie-rcar: fix a potential NULL pointer dereference

[Ulrich Hecht]

> On March 15, 2019 at 8:29 AM Kangjie Lu <kjlu@umn.edu> wrote:
> 
> 
> In case __get_free_pages fails and returns NULL, the fix returns
> -ENOMEM and releases resources to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>

CU
Uli

Re: [PATCH v2] pci: pcie-rcar: fix a potential NULL pointer dereference

[Simon Horman]

On Fri, Mar 15, 2019 at 02:29:43AM -0500, Kangjie Lu wrote:
> In case __get_free_pages fails and returns NULL, the fix returns
> -ENOMEM and releases resources to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

Re: [PATCH v2] pci: pcie-rcar: fix a potential NULL pointer dereference

[Lorenzo Pieralisi]

On Fri, Mar 15, 2019 at 02:29:43AM -0500, Kangjie Lu wrote:
> In case __get_free_pages fails and returns NULL, the fix returns
> -ENOMEM and releases resources to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> 
> ---
> V2 removes the error message.
> ---
>  drivers/pci/controller/pcie-rcar.c | 4 ++++
>  1 file changed, 4 insertions(+)

Applied to pci/rcar for v5.2, thanks.

Lorenzo

> diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
> index c8febb009454..71e55995c058 100644
> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -929,6 +929,10 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
>  
>  	/* setup MSI data target */
>  	msi->pages = __get_free_pages(GFP_KERNEL, 0);
> +	if (!msi->pages) {
> +		err = -ENOMEM;
> +		goto err;
> +	}
>  	base = virt_to_phys((void *)msi->pages);
>  
>  	rcar_pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
> -- 
> 2.17.1
> 

Re: [PATCH] tty: atmel_serial: fix a NULL pointer dereference

[Richard Genoud]

Hi,

Good catch !
Le 14/03/2019 à 08:17, Kangjie Lu a écrit :
> In case dmaengine_prep_dma_cyclic fails, the fix return a proper
> error code to avoid NULL pointer dereference.
> 
you could add:
Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
So that -stable branches get this.

> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/tty/serial/atmel_serial.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 05147fe24343..cf560d05008c 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -1237,8 +1237,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  	dma_cap_set(DMA_CYCLIC, mask);
>  
>  	atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx");
> -	if (atmel_port->chan_rx == NULL)
> +	if (atmel_port->chan_rx == NULL) {
> +		ret = -EINVAL;
>  		goto chan_err;
> +	}
>  	dev_info(port->dev, "using %s for rx DMA transfers\n",
>  		dma_chan_name(atmel_port->chan_rx));
>  
> @@ -1257,6 +1259,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  
>  	if (!nent) {
>  		dev_dbg(port->dev, "need to release resource of dma\n");
> +		ret = -EINVAL;
>  		goto chan_err;
>  	} else {
>  		dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
> @@ -1288,6 +1291,11 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  					 sg_dma_len(&atmel_port->sg_rx)/2,
>  					 DMA_DEV_TO_MEM,
>  					 DMA_PREP_INTERRUPT);
> +	if (!desc) {
> +		dev_err(port->dev, "Preparing DMA cyclic failed\n");
> +		ret = -ENOMEM;
IMHO, we don't really know why dmaengine_prep_dma_cyclic() failed, it
could be because it's already in use, or bad value, or...
(and anyway, we just check if the return value is < 0 in atmel _startup.)
Is there a specific reason you choose -ENOMEM ?
If not, maybe keeping this patch smaller with a simple dev_err()+goto
here would be a better choice.

> +		goto chan_err;
> +	}
>  	desc->callback = atmel_complete_rx_dma;
>  	desc->callback_param = port;
>  	atmel_port->desc_rx = desc;
> @@ -1300,7 +1308,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  	atmel_port->use_dma_rx = 0;
>  	if (atmel_port->chan_rx)
>  		atmel_release_rx_dma(port);
> -	return -EINVAL;
> +	return ret;
>  }
>  
>  static void atmel_uart_timer_callback(struct timer_list *t)
> 

Thanks !

Richard.

[PATCH v2] tty: atmel_serial: fix a NULL pointer dereference

[Kangjie Lu]

Fixes: 34df42f59a60 ("serial: at91: add rx dma support")

In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>

---
V2: simplified the patch as suggested by
Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/atmel_serial.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..41b728d223d1 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
-- 
2.17.1