Re: [RFC V2 3/3] mm: Replace pgtable entry prints with new format

[David Hildenbrand (Arm)]

On 6/12/26 23:26, Hugh Dickins wrote:
> On Fri, 12 Jun 2026, David Hildenbrand (Arm) wrote:
> ...
>>
>> After some off-list discussion, I wonder if we can make our life easier.
>>
>> I think, even with your patch, there is still the case:
>>
>> pr_alert("BUG: Bad page map in process %s  %s:%08llx", current->comm,
>> 	 pgtable_level_to_str(level), entry);
>>
>> Where we cast all entries to an "unsigned long" in the callers. We'd have to rework all
>> that for 128bit entries either way (passing them in some struct instead).
>>
>> I really just extended what we used to do here in print_bad_pte() before commit ec63a44011d.
>>
>> Maybe we should just drop the "print the involved page table entries" thing?
>>
>> I mean, we do have the actual page, and we do have the address in the address space, which
>> we all print.
>>
>> Not sure if the actual page table entries are that relevant?
> 
> The page table entry is BUGgily Bad: we want to see what it looks like
> (sometimes, a sequence of bad page map entries may even show up as ASCII).

But is printing raw page table entries really what we want? I guess to detect
"random corruption" it might help sometimes.

And do we really need information about the full page table walk, or is the last
level good enough?

-- 
Cheers,

David