From 1c7873e3364570ec89343ff4877e0f27a7b21a61 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@google.com>
Date: Sat, 8 Jul 2023 16:04:00 -0700
Subject: [PATCH] mm: lock newly mapped VMA with corrected ordering
Lockdep is certainly right to complain about
(&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_write+0x2d/0x3f
but task is already holding lock:
(&mapping->i_mmap_rwsem){+.+.}-{3:3}, at: mmap_region+0x4dc/0x6db
Invert those to the usual ordering.
Fixes: 33313a747e81 ("mm: lock newly mapped VMA which can be modified after it becomes visible")
Cc: stable@vger.kernel.org
Signed-off-by: Hugh Dickins <hughd@google.com>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/mmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 84c71431a5273..3eda23c9ebe7a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2809,11 +2809,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
if (vma_iter_prealloc(&vmi))
goto close_and_free_vma;
+ /* Lock the VMA since it is modified after insertion into VMA tree */
+ vma_start_write(vma);
if (vma->vm_file)
i_mmap_lock_write(vma->vm_file->f_mapping);
- /* Lock the VMA since it is modified after insertion into VMA tree */
- vma_start_write(vma);
vma_iter_store(&vmi, vma);
mm->map_count++;
if (vma->vm_file) {
--
GitLab