From: Li Xinhai <lixinhai.lxh@xxxxxxxxx> Subject: mm: set vm_next and vm_prev to NULL in vm_area_dup() Set ->vm_next and ->vm_prev to NULL to prevent potential misuse from the new duplicated vma. Currently, only in fork path there are misuse for handling anon_vma. No other bugs been revealed with this patch applied. Link: http://lkml.kernel.org/r/1581150928-3214-4-git-send-email-lixinhai.lxh@xxxxxxxxx Signed-off-by: Li Xinhai <lixinhai.lxh@xxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/fork.c~mm-set-vm_next-and-vm_prev-to-null-in-vm_area_dup +++ a/kernel/fork.c @@ -361,6 +361,7 @@ struct vm_area_struct *vm_area_dup(struc if (new) { *new = *orig; INIT_LIST_HEAD(&new->anon_vma_chain); + new->vm_next = new->vm_prev = NULL; } return new; } @@ -562,7 +563,6 @@ static __latent_entropy int dup_mmap(str } else if (anon_vma_fork(tmp, mpnt)) goto fail_nomem_anon_vma_fork; tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); - tmp->vm_next = tmp->vm_prev = NULL; file = tmp->vm_file; if (file) { struct inode *inode = file_inode(file); _
