Re: [PATCH v2 10/14] hv: vmbus: pin buffer pages across UIO mmap to close the reclaim race

[Nathan Chancellor <nathan@kernel.org>]

On Fri, Oct 09, 2026 at 12:49:37AM +0800, kernel test robot wrote:
> Hi Emerson,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on char-misc/char-misc-testing]
> [also build test WARNING on char-misc/char-misc-next char-misc/char-misc-linus linus/master v7.3-rc6 next-20261008]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Emerson-Busson/hv-vmbus-convert-ring-backing-through-the-chunk-allocator/20261007-160739
> base:   char-misc/char-misc-testing
> patch link:    https://lore.kernel.org/r/20261007190752.336426-11-emersonbusson%40gmail.com
> patch subject: [PATCH v2 10/14] hv: vmbus: pin buffer pages across UIO mmap to close the reclaim race
> config: i386-randconfig-1001-20261008 (https://download.01.org/0day-ci/archive/20261009/202610090058.hvXsWpoT-lkp@intel.com/config)
> compiler: clang version 22.1.3 (https://github.com/llvm/llvm-project e9846648fd6183ee6d8cbdb4502213fcf902a211)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261009/202610090058.hvXsWpoT-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202610090058.hvXsWpoT-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>    In file included from drivers/uio/uio_hv_generic.c:428:
> >> drivers/uio/uio_hv_generic_mmap_test.c:36:34: warning: implicit conversion from 'u64' (aka 'unsigned long long') to 'unsigned long' changes value from 18446744073709551615 to 4294967295 [-Wconstant-conversion]
>       36 |                            hv_uio_mmap_range_valid(8, U64_MAX, 1));
>          |                            ~~~~~~~~~~~~~~~~~~~~~~~    ^~~~~~~

GCC also warns in the same way. Should probably be ULONG_MAX since
'pgoff_t' is 'unsigned long'?

-- 
Cheers,
Nathan