On 07/01/26 10:18 pm, Kevin Brodsky wrote:
> One of the pagemap_ioctl tests attempts to fault in pages by
> memcpy()'ing them to an unused buffer. This probably worked
> originally, but since commit 46036188ea1f ("selftests/mm: build with
> -O2") the compiler is free to optimise away that unused buffer and
> the memcpy() with it. As a result there might not be any resident
> page in the mapping and the test may fail.
>
> We don't need to copy all that memory anyway. Just fault in every
> page.
>
> Cc: Usama Anjum <[email protected]>
> Signed-off-by: Kevin Brodsky <[email protected]>Reviewed-by: Dev Jain <[email protected]> > --- > tools/testing/selftests/mm/pagemap_ioctl.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c > b/tools/testing/selftests/mm/pagemap_ioctl.c > index 2cb5441f29c7..80d7c391f8f5 100644 > --- a/tools/testing/selftests/mm/pagemap_ioctl.c > +++ b/tools/testing/selftests/mm/pagemap_ioctl.c > @@ -1056,7 +1056,6 @@ int sanity_tests(void) > struct page_region *vec; > char *mem, *fmem; > struct stat sbuf; > - char *tmp_buf; > > /* 1. wrong operation */ > mem_size = 10 * page_size; > @@ -1167,8 +1166,7 @@ int sanity_tests(void) > if (fmem == MAP_FAILED) > ksft_exit_fail_msg("error nomem %d %s\n", errno, > strerror(errno)); > > - tmp_buf = malloc(sbuf.st_size); > - memcpy(tmp_buf, fmem, sbuf.st_size); > + force_read_pages_in_range(fmem, sbuf.st_size); > > ret = pagemap_ioctl(fmem, sbuf.st_size, vec, vec_size, 0, 0, > 0, PAGEMAP_NON_WRITTEN_BITS, 0, > PAGEMAP_NON_WRITTEN_BITS);
