Link: https://lkml.kernel.org/r/20250203075206.1452208-1-rcn@xxxxxxxxxx Fixes: 8ebe0a5eaaeb ("mm,madvise,hugetlb: fix unexpected data loss with MADV_DONTNEED on hugetlbfs") Signed-off-by: Ricardo Cañuelo Navarro <rcn@xxxxxxxxxx> Cc: Florent Revest <revest@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/madvise.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/mm/madvise.c~mmmadvisehugetlb-check-for-0-length-range-after-end-address-adjustment +++ a/mm/madvise.c @@ -933,7 +933,16 @@ static long madvise_dontneed_free(struct */ end = vma->vm_end; } - VM_WARN_ON(start >= end); + /* + * If the memory region between start and end was + * originally backed by 4kB pages and then remapped to + * be backed by hugepages while mmap_lock was dropped, + * the adjustment for hugetlb vma above may have rounded + * end down to the start address. + */ + if (start == end) + return 0; + VM_WARN_ON(start > end); } if (behavior == MADV_DONTNEED || behavior == MADV_DONTNEED_LOCKED) _ Patches currently in -mm which might be from rcn@xxxxxxxxxx are mmmadvisehugetlb-check-for-0-length-range-after-end-address-adjustment.patch
