Re: [PATCH v1 2/2] PCI: of_property: Fix uninitialized variable when of_irq_parse_raw() failed

[Lizhi Hou <lizhi.hou@xxxxxxx>]

On 9/29/23 09:27, Bjorn Helgaas wrote:
> On Thu, Sep 28, 2023 at 09:47:11AM -0700, Lizhi Hou wrote:
> > In function of_pci_prop_intr_map(), addr_sz[i] will be uninitialized if
> > of_irq_parse_raw() returns failure. Add addr_sz array initialization. And
> > when parsing irq failed, skip generating interrupt-map pair for the pin.
> Would you mind splitting this into two?  It sounds like it fixes two
> problems: (1) using uninitialized addr_sz[] and (2) skip generating
> interrupt-map pair.
Ok. I will split it into two patches and mark them 'v3'.
> There's also something going on with the pci_swizzle_interrupt_pin()
> change; maybe that should be a third patch so you can explain what's
> going on there?

It is all about to skip the pair which can not be parsed by 
of_irq_parse_raw().  pci_swizzle_interrupt_pin() is moved to the 
beginning of the loop to skip the non parsed pin.


Thanks,

Lizhi

> IIUC this is actually a *v2* (not a v1), since you posted it
> previously as
> https://lore.kernel.org/r/1694801287-17217-2-git-send-email-lizhi.hou@xxxxxxx
> so the next round should be labeled v3.
>
> > Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
> > Reported-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > Closes: https://lore.kernel.org/all/20230911154856.000076c3@xxxxxxxxxx/
> > Reviewed-by: Herve Codina <herve.codina@xxxxxxxxxxx>
> > Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxx>
> > ---
> >   drivers/pci/of_property.c | 25 ++++++++++++++++++-------
> >   1 file changed, 18 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c
> > index 710ec35ba4a1..c2c7334152bc 100644
> > --- a/drivers/pci/of_property.c
> > +++ b/drivers/pci/of_property.c
> > @@ -186,8 +186,8 @@ static int of_pci_prop_interrupts(struct pci_dev *pdev,
> >   static int of_pci_prop_intr_map(struct pci_dev *pdev, struct of_changeset *ocs,
> >   				struct device_node *np)
> >   {
> > +	u32 i, addr_sz[OF_PCI_MAX_INT_PIN] = { 0 }, map_sz = 0;
> >   	struct of_phandle_args out_irq[OF_PCI_MAX_INT_PIN];
> > -	u32 i, addr_sz[OF_PCI_MAX_INT_PIN], map_sz = 0;
> >   	__be32 laddr[OF_PCI_ADDRESS_CELLS] = { 0 };
> >   	u32 int_map_mask[] = { 0xffff00, 0, 0, 7 };
> >   	struct device_node *pnode;
> > @@ -213,33 +213,44 @@ static int of_pci_prop_intr_map(struct pci_dev *pdev, struct of_changeset *ocs,
> >   		out_irq[i].args[0] = pin;
> >   		ret = of_irq_parse_raw(laddr, &out_irq[i]);
> >   		if (ret) {
> > -			pci_err(pdev, "parse irq %d failed, ret %d", pin, ret);
> > +			out_irq[i].np = NULL;
> > +			pci_dbg(pdev, "parse irq %d failed, ret %d", pin, ret);
> >   			continue;
> >   		}
> > -		ret = of_property_read_u32(out_irq[i].np, "#address-cells",
> > -					   &addr_sz[i]);
> > -		if (ret)
> > -			addr_sz[i] = 0;
> > +		of_property_read_u32(out_irq[i].np, "#address-cells",
> > +				     &addr_sz[i]);
> >   	}
> >   
> >   	list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
> >   		for (pin = 1; pin <= OF_PCI_MAX_INT_PIN; pin++) {
> >   			i = pci_swizzle_interrupt_pin(child, pin) - 1;
> > +			if (!out_irq[i].np)
> > +				continue;
> >   			map_sz += 5 + addr_sz[i] + out_irq[i].args_count;
> >   		}
> >   	}
> >   
> > +	/*
> > +	 * Parsing interrupt failed for all pins. In this case, it does not
> > +	 * need to generate interrupt-map property.
> > +	 */
> > +	if (!map_sz)
> > +		return 0;
> > +
> >   	int_map = kcalloc(map_sz, sizeof(u32), GFP_KERNEL);
> >   	mapp = int_map;
> >   
> >   	list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
> >   		for (pin = 1; pin <= OF_PCI_MAX_INT_PIN; pin++) {
> > +			i = pci_swizzle_interrupt_pin(child, pin) - 1;
> > +			if (!out_irq[i].np)
> > +				continue;
> > +
> >   			*mapp = (child->bus->number << 16) |
> >   				(child->devfn << 8);
> >   			mapp += OF_PCI_ADDRESS_CELLS;
> >   			*mapp = pin;
> >   			mapp++;
> > -			i = pci_swizzle_interrupt_pin(child, pin) - 1;
> >   			*mapp = out_irq[i].np->phandle;
> >   			mapp++;
> >   			if (addr_sz[i]) {
> > --
> > 2.34.1