On Tue, Aug 10, 2021 at 11:19 AM John Garry <john.garry@xxxxxxxxxx> wrote: > On 04/08/2021 09:52, Arnd Bergmann wrote: > > This seems a reasonable approach. Do you have a plan for this work? Or > still waiting for the green light? I'm rather busy with other work at the moment, so no particular plans for any time soon. > I have noticed the kernel test robot reporting the following to me, > which seems to be the same issue which was addressed in this series > originally: > > config: s390-randconfig-r032-20210802 (attached as .config) > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project > 4f71f59bf3d9914188a11d0c41bedbb339d36ff5) > ... > All errors (new ones prefixed by >>): > > In file included from drivers/block/null_blk/main.c:12: > In file included from drivers/block/null_blk/null_blk.h:8: > In file included from include/linux/blkdev.h:25: > In file included from include/linux/scatterlist.h:9: > In file included from arch/s390/include/asm/io.h:75: > include/asm-generic/io.h:464:31: warning: performing pointer > arithmetic on a null pointer has undefined behavior > [-Wnull-pointer-arithmetic] > val = __raw_readb(PCI_IOBASE + addr); > > So I imagine lots of people are seeing these. Right, this is the original problem that Niklas was trying to solve. If Niklas has time to get this fixed, I can probably find a way to work with him on finishing up my proposed patch with the changes you suggested. Arnd