linux-kernel - Re: [PATCH v2] mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype

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] [day] [month] [year] [list]

Message-ID: <e95f26dc-4b22-8ede-0da4-511cc03076d1@redhat.com>
Date:   Thu, 2 Sep 2021 14:13:48 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Miaohe Lin <linmiaohe@...wei.com>, akpm@...ux-foundation.org
Cc:     vbabka@...e.cz, peterz@...radead.org, mgorman@...hsingularity.net,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm/page_alloc.c: avoid accessing uninitialized pcp
 page migratetype

On 02.09.21 13:54, Miaohe Lin wrote:
> If it's not prepared to free unref page, the pcp page migratetype is
> unset. Thus We will get rubbish from get_pcppage_migratetype() and
> might list_del &page->lru again after it's already deleted from the
> list leading to grumble about data corruption.
> 
> Fixes: df1acc856923 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock")
> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
> Acked-by: Mel Gorman <mgorman@...hsingularity.net>
> Cc: <stable@...r.kernel.org>
> ---
>   mm/page_alloc.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 9c09dcb24149..a3c6acafa478 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3420,8 +3420,10 @@ void free_unref_page_list(struct list_head *list)
>   	/* Prepare pages for freeing */
>   	list_for_each_entry_safe(page, next, list, lru) {
>   		pfn = page_to_pfn(page);
> -		if (!free_unref_page_prepare(page, pfn, 0))
> +		if (!free_unref_page_prepare(page, pfn, 0)) {
>   			list_del(&page->lru);
> +			continue;
> +		}
>   
>   		/*
>   		 * Free isolated pages directly to the allocator, see
> 

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

-- 
Thanks,

David / dhildenb