On 08/05/22 14:14, Peter Xu wrote:
On Fri, Aug 05, 2022 at 01:03:28PM +0200, David Hildenbrand wrote:
diff --git a/mm/mmap.c b/mm/mmap.c index 61e6135c54ef..462a6b0344ac 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1683,6 +1683,13 @@ int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) return 0;
- /*
* Hugetlb does not require/support writenotify; especially, it does not* support softdirty tracking.*/- if (is_vm_hugetlb_page(vma))
return 0;I'm kind of confused here.. you seems to be fixing up soft-dirty for hugetlb but here it's explicitly forbidden.
Could you explain a bit more on why this patch is needed if (assume there'll be a working) patch 2 being provided?
No comments on the patch, but ...
Since it required little thought, I ran the test program on next-20220802 and was surprised that the issue did not recreate. Even added a simple printk to make sure we were getting into vma_wants_writenotify with a hugetlb vma. We were.
I can easily recreate with an older Fedora kernel.
Will be trying to understand why this is the case.