Re: [syzbot] KMSAN: uninit-value in ax88179_led_setting

[Pavel Skripkin]

Hi David,

On 3/26/22 14:47, David Kahurani wrote:
> > Signed-off-by: David Kahurani <k.kahurani@xxxxxxxxx>
> > Reported-by: syzbot+d3dbdf31fbe9d8f5f311@xxxxxxxxxxxxxxxxxxxxxxxxx
> > ---
> >  drivers/net/usb/ax88179_178a.c | 181 +++++++++++++++++++++++++++------
> >  1 file changed, 152 insertions(+), 29 deletions(-)
> >
> > diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
> > index a31098981..932e21a65 100644
> > --- a/drivers/net/usb/ax88179_178a.c
> > +++ b/drivers/net/usb/ax88179_178a.c
> > @@ -224,9 +224,12 @@ static int __ax88179_write_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
> >   ret = fn(dev, cmd, USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> >   value, index, data, size);

You've changed __ax88179_write_cmd(), but not __ax88179_read_cmd(). I've 
missed it. Changing  __ax88179_write_cmd() does not help with uninit 
value bugs

Also I believe, __ax88179_read_cmd() should have __must_check annotation 
too, since problem came from it in the first place (I mean after added 
sane error handling inside it)

Next thing is ax88179_read_cmd_nopm() still prone to uninit value bugs, 
since it touches uninitialized `buf` in case of __ax88179_read_cmd() 
error...



I remembered why I gave up on fixing this driver... I hope, you have 
more free time and motivation :)




With regards,
Pavel Skripkin