From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 9 Feb 2021 00:31:53 +0000 (-0500)
Subject: mm/mmap: Fix do_brk_munmap() when munmapping an entire VMA or more
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=662fdf25a6e504fd149773b05096c0b485a23911;p=users%2Fjedix%2Flinux-maple.git

mm/mmap: Fix do_brk_munmap() when munmapping an entire VMA or more

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---

diff --git a/mm/mmap.c b/mm/mmap.c
index b50d8fed4da1..b4879e66f87d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2927,7 +2927,10 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
 
 	arch_unmap(mm, newbrk, oldbrk);
 
-	if (likely(vma->vm_start >= newbrk)) { // remove entire mapping(s)
+
+	if (likely((vma->vm_end < oldbrk) ||
+		   ((vma->vm_start == newbrk) && (vma->vm_end == oldbrk)))) {
+		// remove entire mapping(s)
 		mas->last = oldbrk - 1;
 		ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf,
 					  true);