On Sun, 2025-01-05 at 22:23 +0530, Manivannan Sadhasivam wrote:
> On Sun, Jan 05, 2025 at 01:57:51PM +0800, kingdix10@xxxxxx wrote:
> > From: King Dix <kingdix10@xxxxxx>
> >
> > 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@xxxxxx>
>
> Also, please do not send next version as a reply to the previous one.
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
>
> - 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.
