On 7/17/26 09:02, Hongfu Li wrote:
> From: Hongfu Li <[email protected]>
>
> In mremap_dontunmap_partial_mapping_overwrite(), mremap() stores its
> returned remapped address into remapped_mapping, while the BUG_ON
> incorrectly checks dest_mapping instead.
>
> If mremap() fails, dest_mapping still holds a valid pointer obtained from
> the prior mmap() call, making this BUG_ON never trigger at all. Correct
> the check to validate the actual mremap() return value stored in
> remapped_mapping.
>
> Signed-off-by: Hongfu Li <[email protected]>
> ---
> tools/testing/selftests/mm/mremap_dontunmap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/mm/mremap_dontunmap.c
> b/tools/testing/selftests/mm/mremap_dontunmap.c
> index a4f75d836733..96ba537facf7 100644
> --- a/tools/testing/selftests/mm/mremap_dontunmap.c
> +++ b/tools/testing/selftests/mm/mremap_dontunmap.c
> @@ -313,7 +313,7 @@ static void
> mremap_dontunmap_partial_mapping_overwrite(void)
> mremap(source_mapping, 5 * page_size,
> 5 * page_size,
> MREMAP_DONTUNMAP | MREMAP_MAYMOVE | MREMAP_FIXED,
> dest_mapping);
> - BUG_ON(dest_mapping == MAP_FAILED, "mremap");
> + BUG_ON(remapped_mapping == MAP_FAILED, "mremap");
> BUG_ON(dest_mapping != remapped_mapping, "expected to remap to
> dest_mapping");
Given that we know from a previous
BUG_ON(dest_mapping == MAP_FAILED, "mmap");
We can just drop this line completely and rely on the
BUG_ON(dest_mapping != remapped_mapping, "expected to remap to
dest_mapping");
--
Cheers,
David
