Re: [PATCH v5 3/3] asm-generic/io.h: warn in inb() and friends with undefined PCI_IOBASE

[Arnd Bergmann]

On Mon, May 10, 2021 at 3:30 PM kernel test robot <lkp@xxxxxxxxx> wrote:
> All warnings (new ones prefixed by >>):
>
>    In file included from include/linux/kernel.h:10,
>                     from include/linux/list.h:9,
>                     from include/linux/module.h:12,
>                     from drivers/net/arcnet/com20020.c:31:
>    drivers/net/arcnet/com20020.c: In function 'com20020_reset':
> >> include/linux/compiler.h:70:32: warning: 'inbyte' is used uninitialized in this function [-Wuninitialized]
>       70 |   (__if_trace.miss_hit[1]++,1) :  \
>          |                                ^
>    drivers/net/arcnet/com20020.c:286:9: note: 'inbyte' was declared here
>      286 |  u_char inbyte;
>          |         ^~~~~~

This looks like a real problem with the patch: the insb()/insw()/insl() helpers
should memset(buffer, 0xff, size) to avoid using random stack data.

        Arnd