From: Liam Howlett <liam.howlett@xxxxxxxxxx> Subject: mm/mmap.c: don't unlock VMAs in remap_file_pages() Since this call uses MAP_FIXED, do_mmap() will munlock the necessary range. There is also an error in the loop test expression which will evaluate as false and the loop body has never execute. Link: https://lkml.kernel.org/r/20210223235010.2296915-1-Liam.Howlett@xxxxxxxxxx Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Acked-by: Hugh Dickins <hughd@xxxxxxxxxx> Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 18 +----------------- 1 file changed, 1 insertion(+), 17 deletions(-) --- a/mm/mmap.c~mm-mmap-dont-unlock-vmas-in-remap_file_pages +++ a/mm/mmap.c @@ -3029,25 +3029,9 @@ SYSCALL_DEFINE5(remap_file_pages, unsign flags &= MAP_NONBLOCK; flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; - if (vma->vm_flags & VM_LOCKED) { - struct vm_area_struct *tmp; + if (vma->vm_flags & VM_LOCKED) flags |= MAP_LOCKED; - /* drop PG_Mlocked flag for over-mapped range */ - for (tmp = vma; tmp->vm_start >= start + size; - tmp = tmp->vm_next) { - /* - * Split pmd and munlock page on the border - * of the range. - */ - vma_adjust_trans_huge(tmp, start, start + size, 0); - - munlock_vma_pages_range(tmp, - max(tmp->vm_start, start), - min(tmp->vm_end, start + size)); - } - } - file = get_file(vma->vm_file); ret = do_mmap(vma->vm_file, start, size, prot, flags, pgoff, &populate, NULL); _
