Re: [PATCH v2 1/1] hung_task: fix warnings caused by unaligned lock pointers

[Lance Yang <lance.yang@linux.dev>]

On 2025/10/8 18:12, Finn Thain wrote:
> 
> On Wed, 8 Oct 2025, Lance Yang wrote:
> 
>>
>> In other words, we are not just fixing the bug reported by Eero and
>> Geert, but correcting the blocker tracking mechanism's flawed assumption
>> for -stable ;)
>>
>> If you feel this doesn't qualify as a fix, I can change the Fixes: tag
>> to point to the original commit that introduced this flawed mechanism
>> instead.
>>
> 
> That's really a question for the bug reporters. I don't personally have a
> problem with CONFIG_DETECT_HUNG_TASK_BLOCKER so I can't say whether the
> fix meets the requirements set in
> Documentation/process/stable-kernel-rules.rst. And I still don't know

I'm a bit confused, as I recall you previously stating that "It's wrong
and should be fixed"[1].

To clarify, is your current position that it should be fixed in general,
but the fix should not be backported to -stable?

If so, then I have nothing further to add to this thread and am happy
to let the maintainer @Andrew decide.

> what's meant by "unnecessary warnings in a few unexpected cases".

The blocker tracking mechanism will trigger a warning when it
encounters any unaligned lock pointer (e.g., from a packed struct). I
don't think that is the expected behavior. Instead, it should simply
skip any unaligned pointer it cannot handle. For the stable kernels,
at least, this is the correct behavior.

[1] 
https://lore.kernel.org/lkml/6ec95c3f-365b-e352-301b-94ab3d8af73c@linux-m68k.org/