From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Sasha Levin <sashal@kernel.org>,
"Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: akpm@linux-foundation.org, corbet@lwn.net, ljs@kernel.org,
Liam.Howlett@oracle.com, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, skhan@linuxfoundation.org, jackmanb@google.com,
hannes@cmpxchg.org, ziy@nvidia.com, linux-mm@kvack.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 0/7] mm: dual-bitmap page allocator consistency checker
Date: Sat, 25 Apr 2026 07:51:10 +0200 [thread overview]
Message-ID: <b2a15eea-6ed9-4b35-af68-4586554ad2a3@kernel.org> (raw)
In-Reply-To: <aeuZcY0u_7PIQb6R@laps>
On 4/24/26 18:25, Sasha Levin wrote:
> On Fri, Apr 24, 2026 at 05:42:53PM +0200, Vlastimil Babka (SUSE) wrote:
>> On 4/24/26 16:00, Sasha Levin wrote:
>>> Existing memory debugging tools - KASAN, KFENCE, page_poisoning - detect
>>> access violations and content corruption, but none of them can detect
>>> silent corruption in the page allocator's own metadata. If a hardware
>>> bit flip corrupts an allocation bitmap, the allocator hands out a page
>>
>> An allocation what? The page allocator is a buddy allocator, it has no
>> bitmap to track free/allocated state of pages?
>
> You're right, the cover letter is misleading there. Buddy doesn't use a bitmap:
> PageBuddy lives in page_type, the free list is a list, and page->private holds
> the order. The dual-bitmap is new metadata the feature adds, maintained from
> the alloc/free hooks.
Given that you have PageBuddy (first "bit"), could we use a second bit in page_ext?
--
Cheers,
David
next prev parent reply other threads:[~2026-04-25 5:51 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-24 14:00 [RFC 0/7] mm: dual-bitmap page allocator consistency checker Sasha Levin
2026-04-24 14:00 ` [RFC 1/7] mm: add generic dual-bitmap consistency primitives Sasha Levin
2026-04-24 14:00 ` [RFC 2/7] mm: add page consistency checker header Sasha Levin
2026-04-24 14:00 ` [RFC 3/7] mm: add Kconfig options for page consistency checker Sasha Levin
2026-04-24 14:00 ` [RFC 4/7] mm: add page consistency checker implementation Sasha Levin
2026-04-24 14:25 ` David Hildenbrand (Arm)
2026-04-24 14:49 ` Sasha Levin
2026-04-24 15:06 ` Pasha Tatashin
2026-04-24 18:28 ` David Hildenbrand (Arm)
2026-04-24 23:34 ` Sasha Levin
2026-04-25 5:30 ` David Hildenbrand (Arm)
2026-04-25 16:38 ` Sasha Levin
2026-04-24 18:26 ` David Hildenbrand (Arm)
2026-04-24 14:00 ` [RFC 5/7] mm/page_alloc: integrate page consistency hooks Sasha Levin
2026-04-24 14:00 ` [RFC 6/7] Documentation/mm: add page consistency checker documentation Sasha Levin
2026-04-24 14:00 ` [RFC 7/7] mm/page_consistency: add KUnit tests for dual-bitmap primitives Sasha Levin
2026-04-24 15:34 ` [RFC 0/7] mm: dual-bitmap page allocator consistency checker Matthew Wilcox
2026-04-24 15:53 ` Sasha Levin
2026-04-24 15:42 ` Vlastimil Babka (SUSE)
2026-04-24 16:25 ` Sasha Levin
2026-04-25 5:51 ` David Hildenbrand (Arm) [this message]
2026-04-25 16:09 ` Sasha Levin
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