On Mon, 19 Apr 2021 18:41:33 +0200,
Yizhuo Zhai wrote:
>
> Inside the function uaa_to_xfi(), variable "l_timer" could be
> uninitialized if pci_bus_read_config_dword() returns
> PCIBIOS_BAD_REGISTER_NUMBER. However, it is write back to PCI
> config space via pci_write_config_dword(), which is potentially
> unsafe.
Thanks for the patch. But it cannot be taken as is.
First off, practically seen, reading PCI_LATENCY_TIMER would never
fail. And, even if it were to fail, it's not safer at all to proceed
with a value -1.
If any, it should return an error instead. Also, there are a few
other similar PCI config reads and those have to be treated as well.
But it's likely not worth. If it's a device that is used on VM, you
might have more chance to break something unexpectedly, but on a real
hardware, it's not. And it's about the init sequence, which won't
bring to anything actually crashing the kernel.
Takashi
>
> Signed-off-by: Yizhuo <yzhai003@xxxxxxx>
> ---
> sound/pci/ctxfi/cthw20k1.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sound/pci/ctxfi/cthw20k1.c b/sound/pci/ctxfi/cthw20k1.c
> index 0cea4982ed7d..7c3436499974 100644
> --- a/sound/pci/ctxfi/cthw20k1.c
> +++ b/sound/pci/ctxfi/cthw20k1.c
> @@ -1789,7 +1789,7 @@ static struct capabilities hw_capabilities(struct hw
> *hw)
> static int uaa_to_xfi(struct pci_dev *pci)
> {
> unsigned int bar0, bar1, bar2, bar3, bar4, bar5;
> - unsigned int cmd, irq, cl_size, l_timer, pwr;
> + unsigned int cmd, irq, cl_size, l_timer = ~0, pwr;
> unsigned int is_uaa;
> unsigned int data[4] = {0};
> unsigned int io_base;
> --
> 2.31.1
>
> --
> Kind Regards,
>
> Yizhuo Zhai
>
> Computer Science, Graduate Student
> University of California, Riverside
>
>
