> > 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");
The subsequent BUG_ON comparison will implicitly catch the MAP_FAILED condition, so this check is redundant. This line will be dropped in the next revision. Thanks a lot for your review. Best regards, Hongfu
