linux-kernel - Re: [PATCH v2] mm, slab: clean up slab->obj

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Message-ID: <da89dcd6-9369-4a87-9794-a0bf5772509b@suse.cz>
Date: Thu, 24 Apr 2025 18:48:46 +0200
From: Vlastimil Babka <vbabka@...e.cz>
To: Andy Shevchenko <andriy.shevchenko@...el.com>,
 Zhenhua Huang <quic_zhenhuah@...cinc.com>
Cc: cl@...ux.com, rientjes@...gle.com, roman.gushchin@...ux.dev,
 harry.yoo@...cle.com, surenb@...gle.com, pasha.tatashin@...een.com,
 akpm@...ux-foundation.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
 quic_tingweiz@...cinc.com, stable@...r.kernel.org
Subject: Re: [PATCH v2] mm, slab: clean up slab->obj_exts always

On 4/24/25 18:34, Andy Shevchenko wrote:
> On Mon, Apr 21, 2025 at 03:52:32PM +0800, Zhenhua Huang wrote:
>> When memory allocation profiling is disabled at runtime or due to an
>> error, shutdown_mem_profiling() is called: slab->obj_exts which
>> previously allocated remains.
>> It won't be cleared by unaccount_slab() because of
>> mem_alloc_profiling_enabled() not true. It's incorrect, slab->obj_exts
>> should always be cleaned up in unaccount_slab() to avoid following error:
>> 
>> [...]BUG: Bad page state in process...
>> ..
>> [...]page dumped because: page still charged to cgroup
> 
> Please, always compile test with `make W=1`. Since CONFIG_WERROR=y this
> effectively breaks the build with Clang.

I don't see why, nor observe any W=1 warnings, can you be more specific? Thanks.