From 1c7873e3364570ec89343ff4877e0f27a7b21a61 Mon Sep 17 00:00:00 2001 From: Hugh Dickins 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 Tested-by: Suren Baghdasaryan Signed-off-by: Linus Torvalds --- mm/mmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 84c71431a527..3eda23c9ebe7 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2809,11 +2809,11 @@ cannot_expand: 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) {