[PATCH] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[PATCH] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[kingdix10]

From: King Dix <kingdix10@qq.com>

When using devm_request_mem_region to request a resource, if the passed
variable is a stack string variable, it will lead to an oops issue when
eecuting the command cat /proc/iomem.

Fix this by replacing outbound_name with the name of the previously
requested resource.

Signed-off-by: King Dix <kingdix10@qq.com>
---
 drivers/pci/controller/pcie-rcar-ep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
index 047e2cef5afc..464f8f29390c 100644
--- a/drivers/pci/controller/pcie-rcar-ep.c
+++ b/drivers/pci/controller/pcie-rcar-ep.c
@@ -107,7 +107,7 @@ static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep,
 		}
 		if (!devm_request_mem_region(&pdev->dev, res->start,
 					     resource_size(res),
-					     outbound_name)) {
+						 res->name)) {
 			dev_err(pcie->dev, "Cannot request memory region %s.\n",
 				outbound_name);
 			return -EIO;
-- 
2.43.0

Re: [PATCH] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[Sergey Shtylyov]

On 1/4/25 6:39 AM, kingdix10@qq.com wrote:

> From: King Dix <kingdix10@qq.com>
> 
> When using devm_request_mem_region to request a resource, if the passed
> variable is a stack string variable, it will lead to an oops issue when
> eecuting the command cat /proc/iomem.
> 
> Fix this by replacing outbound_name with the name of the previously
> requested resource.
> 
> Signed-off-by: King Dix <kingdix10@qq.com>
> ---
>  drivers/pci/controller/pcie-rcar-ep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
> index 047e2cef5afc..464f8f29390c 100644
> --- a/drivers/pci/controller/pcie-rcar-ep.c
> +++ b/drivers/pci/controller/pcie-rcar-ep.c
> @@ -107,7 +107,7 @@ static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep,
>  		}
>  		if (!devm_request_mem_region(&pdev->dev, res->start,
>  					     resource_size(res),
> -					     outbound_name)) {
> +						 res->name)) {

   Why this strange indentation?

[...]

MBR, Sergey

[PATCH v2] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[kingdix10]

From: King Dix <kingdix10@qq.com>

When using devm_request_mem_region to request a resource, if the passed
variable is a stack string variable, it will lead to an oops issue when
eecuting the command cat /proc/iomem.

Fix this by replacing outbound_name with the name of the previously
requested resource.

Signed-off-by: King Dix <kingdix10@qq.com>
---
Changes in v2:
  - Fix the code indentation issue.
---
 drivers/pci/controller/pcie-rcar-ep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
index 047e2cef5afc..c5e0d025bc43 100644
--- a/drivers/pci/controller/pcie-rcar-ep.c
+++ b/drivers/pci/controller/pcie-rcar-ep.c
@@ -107,7 +107,7 @@ static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep,
 		}
 		if (!devm_request_mem_region(&pdev->dev, res->start,
 					     resource_size(res),
-					     outbound_name)) {
+					     res->name)) {
 			dev_err(pcie->dev, "Cannot request memory region %s.\n",
 				outbound_name);
 			return -EIO;
-- 
2.43.0

Re: [PATCH v2] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[Manivannan Sadhasivam]

On Sun, Jan 05, 2025 at 01:57:51PM +0800, kingdix10@qq.com wrote:
> From: King Dix <kingdix10@qq.com>
> 
> When using devm_request_mem_region to request a resource, if the passed
> variable is a stack string variable, it will lead to an oops issue when
> eecuting the command cat /proc/iomem.
> 

Is this your observation or you saw the oops? If the latter, please include
the relevant log snippet for reference.

> Fix this by replacing outbound_name with the name of the previously
> requested resource.
> 
> Signed-off-by: King Dix <kingdix10@qq.com>

Also, please do not send next version as a reply to the previous one.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
> Changes in v2:
>   - Fix the code indentation issue.
> ---
>  drivers/pci/controller/pcie-rcar-ep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
> index 047e2cef5afc..c5e0d025bc43 100644
> --- a/drivers/pci/controller/pcie-rcar-ep.c
> +++ b/drivers/pci/controller/pcie-rcar-ep.c
> @@ -107,7 +107,7 @@ static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep,
>  		}
>  		if (!devm_request_mem_region(&pdev->dev, res->start,
>  					     resource_size(res),
> -					     outbound_name)) {
> +					     res->name)) {
>  			dev_err(pcie->dev, "Cannot request memory region %s.\n",
>  				outbound_name);
>  			return -EIO;
> -- 
> 2.43.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[Lad, Prabhakar]

On Sun, Jan 5, 2025 at 6:03 AM <kingdix10@qq.com> wrote:
>
> From: King Dix <kingdix10@qq.com>
>
> When using devm_request_mem_region to request a resource, if the passed
> variable is a stack string variable, it will lead to an oops issue when
> eecuting the command cat /proc/iomem.
>
s/eecuting/executing

> Fix this by replacing outbound_name with the name of the previously
> requested resource.
>
Fixes: 2a6d0d63d999 ("PCI: rcar: Add endpoint mode support")
> Signed-off-by: King Dix <kingdix10@qq.com>
> ---
> Changes in v2:
>   - Fix the code indentation issue.
> ---
>  drivers/pci/controller/pcie-rcar-ep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
With the above fixed,

Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Cheers,
Prabhakar

> diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
> index 047e2cef5afc..c5e0d025bc43 100644
> --- a/drivers/pci/controller/pcie-rcar-ep.c
> +++ b/drivers/pci/controller/pcie-rcar-ep.c
> @@ -107,7 +107,7 @@ static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep,
>                 }
>                 if (!devm_request_mem_region(&pdev->dev, res->start,
>                                              resource_size(res),
> -                                            outbound_name)) {
> +                                            res->name)) {
>                         dev_err(pcie->dev, "Cannot request memory region %s.\n",
>                                 outbound_name);
>                         return -EIO;
> --
> 2.43.0
>
>

Re: [PATCH v2] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[kingdix10]

On Sun, 2025-01-05 at 22:23 +0530, Manivannan Sadhasivam wrote:
> On Sun, Jan 05, 2025 at 01:57:51PM +0800, kingdix10@qq.com wrote:
> > From: King Dix <kingdix10@qq.com>
> > 
> > When using devm_request_mem_region to request a resource, if the
> > passed
> > variable is a stack string variable, it will lead to an oops issue
> > when
> > eecuting the command cat /proc/iomem.
> > 
> 
> Is this your observation or you saw the oops? If the latter, please
> include
> the relevant log snippet for reference.
> 
> > Fix this by replacing outbound_name with the name of the previously
> > requested resource.
> > 
> > Signed-off-by: King Dix <kingdix10@qq.com>
> 
> Also, please do not send next version as a reply to the previous one.
> 
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> 
> - Mani
> 
> > ---
> > Changes in v2:
> >   - Fix the code indentation issue.
> > ---
> >  drivers/pci/controller/pcie-rcar-ep.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pci/controller/pcie-rcar-ep.c
> > b/drivers/pci/controller/pcie-rcar-ep.c
> > index 047e2cef5afc..c5e0d025bc43 100644
> > --- a/drivers/pci/controller/pcie-rcar-ep.c
> > +++ b/drivers/pci/controller/pcie-rcar-ep.c
> > @@ -107,7 +107,7 @@ static int
> > rcar_pcie_parse_outbound_ranges(struct rcar_pcie_endpoint *ep,
> >  		}
> >  		if (!devm_request_mem_region(&pdev->dev, res->start,
> >  					     resource_size(res),
> > -					     outbound_name)) {
> > +					     res->name)) {
> >  			dev_err(pcie->dev, "Cannot request memory region %s.\n",
> >  				outbound_name);
> >  			return -EIO;
> > -- 
> > 2.43.0
> > 
> 

This is only a potential issue that I found while analyzing the code.
When cat /proc/iomem is executed, the r_show function called, it will 
access the name parameter of resource. Specifically, if a variable on
the stack is used when calling devm_request_mem_region, it will lead to
an oops problem.