+ selftests-mm-fix-bug_on-checking-wrong-variable-in-mremap_dontunmap.patch added to mm-new branch

The patch titled
     Subject: selftests/mm: Fix BUG_ON checking wrong variable in mremap_dontunmap
has been added to the -mm mm-new branch.  Its filename is
     selftests-mm-fix-bug_on-checking-wrong-variable-in-mremap_dontunmap.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-fix-bug_on-checking-wrong-variable-in-mremap_dontunmap.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Hongfu Li <[email protected]>
Subject: selftests/mm: Fix BUG_ON checking wrong variable in mremap_dontunmap
Date: Fri, 17 Jul 2026 15:02:51 +0800

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.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Hongfu Li <[email protected]>
Reviewed-by: SJ Park <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 tools/testing/selftests/mm/mremap_dontunmap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/testing/selftests/mm/mremap_dontunmap.c~selftests-mm-fix-bug_on-checking-wrong-variable-in-mremap_dontunmap
+++ a/tools/testing/selftests/mm/mremap_dontunmap.c
@@ -313,7 +313,7 @@ static void mremap_dontunmap_partial_map
 	    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");
 
 	BUG_ON(check_region_contains_byte(source_mapping, 5 * page_size, 0) !=
_

Patches currently in -mm which might be from [email protected] are

selftests-mm-move-pkey-selftest-helpers-to-pkey_utilc.patch
selftests-mm-unify-pkey-sighandler-selftest-assertions-and-tracing.patch
selftests-mm-use-pkey_assert-on-clone_raw-failure-in-pkey-test.patch
selftests-mm-add-missing-mmap-return-checks-in-pkey-tests.patch
selftests-mm-add-missing-pthread_create-return-checks-in-pkey-tests.patch
selftests-mm-fix-clone-cleartid-race-in-pkey-sighandler-tests.patch
selftests-mm-fix-memleak-in-migration-benchmark.patch
selftests-mm-factor-out-hmm_buffer_alloc-to-consolidate-buffer-setup.patch
selftests-mm-fix-bug_on-checking-wrong-variable-in-mremap_dontunmap.patch