Re: [PATCH v4] mm: hwposion: support recovery from ksm_might_need_to_copy()

[Naoya Horiguchi]

On Wed, Feb 01, 2023 at 03:44:33PM +0800, Kefeng Wang wrote:
> When the kernel copy a page from ksm_might_need_to_copy(), but runs
> into an uncorrectable error, it will crash since poisoned page is
> consumed by kernel, this is similar to the issue recently fixed by
> Copy-on-write poison recovery.
> 
> When an error is detected during the page copy, return VM_FAULT_HWPOISON
> in do_swap_page(), and install a hwpoison entry in unuse_pte() when
> swapoff, which help us to avoid system crash. Note, memory failure on
> a KSM page will be skipped, but still call memory_failure_queue() to
> be consistent with general memory failure process, and we could support
> KSM page recovery in the feature.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>

Looks good to me, thank you.

Reviewed-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>