On 2/18/26 19:42, Audra Mitchell wrote: > On architectures with separate user address space, such as s390 or > those without an MMU, the call to __access_ok will return true.
Where is this __access_ok() you mention here? Somewhere in fs/proc/task_mmu.c? > The soft-dirty test attempts to check if the PAGEMAP_SCAN feature > is supported by providing an invalid address and expecting > __access_ok to return false, thus throwing an EFAULT error on return. Where in the soft-dirty test is that triggered? I'm wondering whether the soft-dirty test should be adjusted, but I did not yet understand from where this behavior is triggered. > Because of this assumption, this check will always fail for the > architectures aforementioned. Update the supported check to handle > the return being zero for these types of cases. It would be great to include the output of an actual test case (soft-dirty?) that is affected by this before/after your change (likely on s390x where it seems to trigger). Do we have a Fixes: tag? > > Signed-off-by: Audra Mitchell <[email protected]> > --- > tools/testing/selftests/mm/vm_util.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/mm/vm_util.c > b/tools/testing/selftests/mm/vm_util.c > index d954bf91afd5..3bb7d322101c 100644 > --- a/tools/testing/selftests/mm/vm_util.c > +++ b/tools/testing/selftests/mm/vm_util.c > @@ -77,10 +77,8 @@ static bool pagemap_scan_supported(int fd, char *start) > > /* Provide an invalid address in order to trigger EFAULT. */ > ret = __pagemap_scan_get_categories(fd, start, (struct page_region *) > ~0UL); > - if (ret == 0) > - ksft_exit_fail_msg("PAGEMAP_SCAN succeeded unexpectedly\n"); > > - supported = errno == EFAULT; > + supported = (ret == 0) || (errno == EFAULT); > > return supported; > } -- Cheers, David
