Re: [PATCH v4] PCI: rcar-ep: Fix the issue of the name parameter when calling devm_request_mem_region

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Jan 07, 2025 at 09:51:23PM +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
> executing the command cat /proc/iomem.
> 
> Fix this by replacing outbound_name with the name of the previously
> requested resource.

Thanks a lot for doing this work!

Add "()" after function names in subject and commit log.

Please include a couple lines of the oops message to help people
connect the problem with the fix.

I suppose you found this by tripping over it.  Can you look through
the other callers of devm_request_mem_region() and similar interfaces,
at least in drivers/pci, and make sure there are no other similar
errors?

> Fixes: 2a6d0d63d999 ("PCI: rcar: Add endpoint mode support")
> 
> Signed-off-by: King Dix <kingdix10@qq.com>
> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> Changes in v4:
>   - Add more information to the comment.
> Changes in v3:
>   - Fix the spelling issue in the comment.
> 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
>