On Fri, 19 Oct 2018 12:04:39 -0400 jglisse@redhat.com wrote:
From: Ralph Campbell rcampbell@nvidia.com
In hmm_mirror_unregister(), mm->hmm is set to NULL and then mmu_notifier_unregister_no_release() is called. That creates a small window where mmu_notifier can call mmu_notifier_ops with mm->hmm equal to NULL. Fix this by first unregistering mmu notifier callbacks and then setting mm->hmm to NULL.
Similarly in hmm_register(), set mm->hmm before registering mmu_notifier callbacks so callback functions always see mm->hmm set.
Signed-off-by: Ralph Campbell rcampbell@nvidia.com Reviewed-by: John Hubbard jhubbard@nvidia.com Reviewed-by: Jérôme Glisse jglisse@redhat.com Reviewed-by: Balbir Singh bsingharora@gmail.com Cc: Andrew Morton akpm@linux-foundation.org Cc: stable@vger.kernel.org
I added your Signed-off-by: to this one. It's required since you were on the patch delivery path.