On 10/10/2019 06.15, Wei Yang wrote:
On Thu, Oct 10, 2019 at 10:36:01AM +0800, Wei Yang wrote:
Hi, Qian, Shakeel
Thanks for testing.
Sounds I missed some case to handle. anon_vma_clone() now would be called in
vma_adjust, which is a different case when it is introduced.
Well, I have to correct my statement. The reason is we may did something more
in anon_vma_clone().
Here is a quick fix, while I need to go through all the cases carefully.
Oops, I've overlooked this case too.
You have to check src->anon_vma
otherwise in __split_vma or copy_vma dst could pick completely random anon_vma.
Also checking prev will not hurt, just to be sure.
So, something like this should work:
if (!dst->anon_vma && src->anon_vma &&
prev && pprev && pprev->anon_vma == src->anon_vma)
dst->anon_vma = prev->anon_vma;
diff --git a/mm/rmap.c b/mm/rmap.c
index 12f6c3d7fd9d..2844f442208d 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -271,7 +271,7 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
* 1. Parent has vm_prev, which implies we have vm_prev.
* 2. Parent and its vm_prev have the same anon_vma.
*/
- if (pprev && pprev->anon_vma == src->anon_vma)
+ if (!dst->anon_vma && pprev && pprev->anon_vma == src->anon_vma)
dst->anon_vma = prev->anon_vma;
list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) {
BTW, do you have the specific test case? So that I could verify my change. The
kernel build test doesn't trigger this.
Thanks a lot :-)
On Wed, Oct 09, 2019 at 03:21:11PM -0700, Shakeel Butt wrote:
--
Wei Yang
Help you, Help me
