linux-kernel - Re: [PATCH v1 2/2] PCI: of_property: Fix uninitialized variable when of_irq_parse

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Message-ID: <cf831eb0-2f21-37eb-f9a3-66ba61aba1bb@amd.com>
Date:   Fri, 29 Sep 2023 09:40:34 -0700
From:   Lizhi Hou <lizhi.hou@....com>
To:     Bjorn Helgaas <helgaas@...nel.org>
CC:     <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <herve.codina@...tlin.com>,
        <Jonathan.Cameron@...wei.com>, <bhelgaas@...gle.com>,
        <robh@...nel.org>
Subject: Re: [PATCH v1 2/2] PCI: of_property: Fix uninitialized variable when
 of_irq_parse_raw() failed


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@amd.com
> so the next round should be labeled v3.
>
>> Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
>> Reported-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
>> Closes: https://lore.kernel.org/all/20230911154856.000076c3@Huawei.com/
>> Reviewed-by: Herve Codina <herve.codina@...tlin.com>
>> Signed-off-by: Lizhi Hou <lizhi.hou@....com>
>> ---
>>   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
>>