Re: [PATCH] HID: amd_sfh: Validate BAR 2 as memory-mapped I/O in probe

[Jiri Kosina]

On Sat, 15 Aug 2026, Preetam Sundar Das wrote:

> Syzbot reported a page fault in amd_mp2_pci_probe(). The fuzzer creates
> a malicious PCI device where BAR 2 is defined as an I/O port rather
> than a memory-mapped I/O (MMIO) region.
> 
> The driver previously assumed BAR 2 would always be MMIO and blindly
> passed the I/O port address to readl(), causing a fatal page fault
> when the CPU attempted to read from restricted memory.
> 
> Fix this by explicitly checking the PCI resource flags after waking
> the device. If BAR 2 is not an IORESOURCE_MEM region, safely reject
> the device with -EINVAL to prevent the panic.
> 
> Fixes: 4f567b9f8141 ("SFH: PCIe driver to add support of AMD sensor fusion hub")
> Reported-by: syzbot+4eadd4dfe9e66522bae8@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?id=227a9acbe565367eb7a1277b47115df8706d9a12
> 
> Signed-off-by: Preetam Sundar Das <daspreetam4@xxxxxxxxx>

Basavaraj, can I please get your Ack/Reviewed-by on this one?

Thanks.

> ---
>  drivers/hid/amd-sfh-hid/amd_sfh_pcie.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
> index 4b81cebdc335..aef105a81570 100644
> --- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
> +++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
> @@ -451,6 +451,9 @@ static int amd_mp2_pci_probe(struct pci_dev *pdev, const struct pci_device_id *i
>  	if (rc)
>  		return rc;
>  
> +	if (!(pci_resource_flags(pdev, 2) & IORESOURCE_MEM))
> +		return -EINVAL;
> +
>  	rc = pcim_iomap_regions(pdev, BIT(2), DRIVER_NAME);
>  	if (rc)
>  		return rc;
> -- 
> 2.43.0
> 

-- 
Jiri Kosina
SUSE Labs