From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Sat, 10 Oct 2020 01:40:55 +0000 (-0400)
Subject: maple_tree: Fix ltp shmt09 by checking if vma->vm_anon before locking in vma_mt_brk()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a7eec25de67c0855a1f898e6e4eeeedb12b884dc;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Fix ltp shmt09 by checking if vma->vm_anon before locking in vma_mt_brk()

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

diff --git a/mm/mmap.c b/mm/mmap.c
index 26b1e729382e..5b04a4e79019 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -624,8 +624,10 @@ void vma_mt_brk(struct vm_area_struct *vma, unsigned long new_end)
 {
 	bool store = false;
 
-	anon_vma_lock_write(vma->anon_vma);
-	anon_vma_interval_tree_pre_update_vma(vma);
+	if (vma->anon_vma) {
+		anon_vma_lock_write(vma->anon_vma);
+		anon_vma_interval_tree_pre_update_vma(vma);
+	}
 
 	// changing the back.
 	if (vma->vm_end > new_end) {
@@ -639,8 +641,10 @@ void vma_mt_brk(struct vm_area_struct *vma, unsigned long new_end)
 		vma_mt_store(vma->vm_mm, vma);
 
 
-	anon_vma_interval_tree_post_update_vma(vma);
-	anon_vma_unlock_write(vma->anon_vma);
+	if (vma->anon_vma) {
+		anon_vma_interval_tree_post_update_vma(vma);
+		anon_vma_unlock_write(vma->anon_vma);
+	}
 }
 
 static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -2922,8 +2926,6 @@ static int do_brk_munmap(struct vm_area_struct *vma, unsigned long newbrk,
 	// Change the oldbrk of vma to the newbrk of the munmap area
 	vma_adjust_trans_huge(vma, vma->vm_start, newbrk, 0);
 	vma_mt_brk(vma, newbrk);
-	// Handle usertfaults here.
-	//
 
 	unmap_pages = vma_pages(&unmap);
 	if (unmap.vm_flags & VM_LOCKED) {