From e39a4b332df69f6850efda5ce6d932ef14a39042 Mon Sep 17 00:00:00 2001 From: Li Xinhai Date: Mon, 6 Apr 2020 20:03:39 -0700 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. Signed-off-by: Li Xinhai Signed-off-by: Andrew Morton Acked-by: Kirill A. Shutemov Cc: Matthew Wilcox Cc: Johannes Weiner Cc: Rik van Riel Link: http://lkml.kernel.org/r/1581150928-3214-4-git-send-email-lixinhai.lxh@gmail.com Signed-off-by: Linus Torvalds --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index d3a5915d3cfe..4385f3d639f2 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -361,6 +361,7 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) 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(struct mm_struct *mm, } 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); -- cgit v1.2.3