When unmapping VM_HUGETLB mappings, vm flags need to be updated. Since the vmas have been detached, so it sounds safe to update vm flags with read mmap_sem.
Cc: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Reviewed-by: Matthew Wilcox <[email protected]> Signed-off-by: Yang Shi <[email protected]> --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index 982dd00..490340e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2777,7 +2777,7 @@ static int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, * update vm_flags. */ if (downgrade && - (tmp->vm_flags & (VM_HUGETLB | VM_PFNMAP))) + (tmp->vm_flags & VM_PFNMAP)) downgrade = false; tmp = tmp->vm_next; -- 1.8.3.1
