Re: [PATCH] LoongArch: add p?d_leaf() definitions

From: Hongchen Zhang
Date: Wed Sep 06 2023 - 04:23:01 EST


On 2023/9/6 下午4:08, David Hildenbrand wrote:
On 06.09.23 10:06, Hongchen Zhang wrote:
Hi David,

On 2023/9/6 pm 3:42, David Hildenbrand wrote:
On 05.09.23 08:49, Hongchen Zhang wrote:
When I do LTP test, LTP test case ksm06 caused panic at
     break_ksm_pmd_entry
       -> pmd_leaf (Huge page table but False)
       -> pte_present (panic)


Probably there are other problematic bits without that can trigger that?
I suspect walk_page_range*() callers might be affected,
I rechecked the code and found that other architectures that support
THP have defined pmd_leaf.
So there is not problem on other architectures.

I meant other walk_page_range*() callers on loongarch might similarly be affected. IOW, KSM might not be the only bit being able to trigger such panics on loongarch.
Yes, perf_get_pgtable_size and vmalloc_to_page also call pmd_leaf.
So they may also trigger this issue on LoongArch.



--
Best Regards
Hongchen Zhang