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Subject: Re: [PATCH v2] mm/swapfile: unuse_pte can map random data if swap
 read fails
To:     David Hildenbrand <david@redhat.com>, <akpm@linux-foundation.org>
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From:   Miaohe Lin <linmiaohe@huawei.com>
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On 2022/4/19 19:46, David Hildenbrand wrote:
...
>> Do you mean that we should set the pfn to 0 for the hwpoison marker so that we can
>> distinguish swapin error case from real hwpoison case?
> 
> I am not sure if we really have to distinguish. However, "0" seems to
> make sense to indicate "this is not an actual problematic PFN, the
> information is simply no longer around due to a hardware issue.
> 

IMHO, we have to distinguish. For example, we might need to return VM_FAULT_SIGBUS
instead of VM_FAULT_HWPOISON when user accesses the error page. Or should we simply
return VM_FAULT_HWPOISON to simplify the handling?

Thanks!