linux-kernel - Re: [PATCH v3 2/2] alloc_tag: mark pages reserved during CMA activation as not tagged

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Message-ID: <be75dbc3-3137-44a2-af45-5454728c98a2@redhat.com>
Date: Tue, 13 Aug 2024 17:09:09 +0200
From: David Hildenbrand <david@...hat.com>
To: Suren Baghdasaryan <surenb@...gle.com>, akpm@...ux-foundation.org
Cc: kent.overstreet@...ux.dev, vbabka@...e.cz, pasha.tatashin@...een.com,
 souravpanda@...gle.com, keescook@...omium.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, stable@...r.kernel.org
Subject: Re: [PATCH v3 2/2] alloc_tag: mark pages reserved during CMA
 activation as not tagged

On 13.08.24 17:07, Suren Baghdasaryan wrote:
> During CMA activation, pages in CMA area are prepared and then freed
> without being allocated. This triggers warnings when memory allocation
> debug config (CONFIG_MEM_ALLOC_PROFILING_DEBUG) is enabled. Fix this
> by marking these pages not tagged before freeing them.
> 
> Fixes: d224eb0287fb ("codetag: debug: mark codetags for reserved pages as empty")
> Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
> Cc: stable@...r.kernel.org # v6.10
> ---
> Changes since v2 [1]:
> - Add and use clear_page_tag_ref helper, per David Hildenbrand
> 
> https://lore.kernel.org/all/20240812192428.151825-1-surenb@google.com/
> 
>   mm/mm_init.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 907c46b0773f..13c4060bb01a 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -2245,6 +2245,8 @@ void __init init_cma_reserved_pageblock(struct page *page)
>   
>   	set_pageblock_migratetype(page, MIGRATE_CMA);
>   	set_page_refcounted(page);
> +	/* pages were reserved and not allocated */
> +	clear_page_tag_ref(page);
>   	__free_pages(page, pageblock_order);
>   
>   	adjust_managed_page_count(page, pageblock_nr_pages);

Acked-by: David Hildenbrand <david@...hat.com>

-- 
Cheers,

David / dhildenb