On success, mmap should return the begin address of newly mapped area,
but patch "mm: mmap: merge vma after call_mmap() if possible"
set vm_start of newly merged vma to return value addr.
Users of mmap will get wrong address if vma is merged after call_mmap().
We fix this by moving the assignment to addr before merging vma.
Fixes: d70cec898324 ("mm: mmap: merge vma after call_mmap() if possible")
Signed-off-by: Liu Zixian <liuzixian4@xxxxxxxxxx>
---
mm/mmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index d91ecb00d38c..9199b5e8cc1e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1820,12 +1820,12 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
* and cause general protection fault ultimately.
*/
fput(vma->vm_file);
- vm_area_free(vma);
- vma = merge;
/* Update vm_flags and possible addr to pick up the change. We don't
* warn here if addr changed as the vma is not linked by vma_link().
*/
addr = vma->vm_start;
+ vm_area_free(vma);
+ vma = merge;
vm_flags = vma->vm_flags;
goto unmap_writable;
}
--
2.23.0
