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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3fa8182f-0195-43ee-b163-f908a9e2cba3@linux.dev>
Date: Wed, 8 Oct 2025 21:48:36 +0800
From: Lance Yang <lance.yang@...ux.dev>
To: Finn Thain <fthain@...ux-m68k.org>,
 Andrew Morton <akpm@...ux-foundation.org>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>,
 Eero Tamminen <oak@...sinkinet.fi>,
 Kent Overstreet <kent.overstreet@...ux.dev>, amaindex@...look.com,
 anna.schumaker@...cle.com, boqun.feng@...il.com, ioworker0@...il.com,
 joel.granados@...nel.org, jstultz@...gle.com, leonylgao@...cent.com,
 linux-kernel@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
 longman@...hat.com, mhiramat@...nel.org, mingo@...hat.com,
 mingzhe.yang@...com, peterz@...radead.org, rostedt@...dmis.org,
 senozhatsky@...omium.org, tfiga@...omium.org, will@...nel.org,
 stable@...r.kernel.org
Subject: Re: [PATCH v2 1/1] hung_task: fix warnings caused by unaligned lock
 pointers



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/