From: Lance Yang <lance.yang@linux.dev>
To: david@kernel.org
Cc: vbabka@kernel.org, ziy@nvidia.com, akpm@linux-foundation.org,
surenb@google.com, mhocko@suse.com, jackmanb@google.com,
hannes@cmpxchg.org, ljs@kernel.org, liam@infradead.org,
rppt@kernel.org, yuzhao@google.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Lance Yang <lance.yang@linux.dev>
Subject: Re: [PATCH] mm/page_alloc: free allocated PFNs if the range does not match
Date: Tue, 30 Jun 2026 22:47:14 +0800 [thread overview]
Message-ID: <20260630144714.66550-1-lance.yang@linux.dev> (raw)
In-Reply-To: <d44ae8a5-ec70-456b-92a0-ce7ccabf6917@kernel.org>
On Tue, Jun 30, 2026 at 03:39:56PM +0200, David Hildenbrand (Arm) wrote:
>On 6/30/26 09:44, Vlastimil Babka (SUSE) wrote:
>> On 6/30/26 03:35, Zi Yan wrote:
>>> When using __GFP_COMP in alloc_contig_frozen_range(), if the allocated
>>> range does not match the requested one, the code errors out with EINVAL
>>> without freeing the allocated PFNs and causes free page leaks. Fix it by
>>> calling release_free_list() in the error path.
>>>
>>> The issue is reported by Sashiko[1].
>>
>> So this?
>> Reported-by: Sashiko <sashiko-bot@kernel.org>
>>
>>> Fixes: e98337d11bbd ("mm/contig_alloc: support __GFP_COMP")
>>> Link: https://sashiko.dev/#/patchset/20260628-keep-subpage-private-zero-at-free-v1-0-f4ce3930d10f@nvidia.com [1]
>>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>>> Cc: stable@vger.kernel.org
>>
>> Hm well, it's a path that warns, can only happen due to a development error?
>> Not sure we care about stable then. Anyway.
>>
>
>If someone would run into the WARN we would already be in Fixes: territory.
>
>it's a path that should never be executed. If it does, the real issue must be fixed.
>
>So (a) I don't think this is stable material (b) I am skeptical that this is
>even a Fixes and (c) I am wondering whether we should touch this *at all*.
FWIW, this patch looks fine defensively, but probably not a stable
material unless we know a real caller can hit it :)
Cheers, Lance
next prev parent reply other threads:[~2026-06-30 14:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-30 1:35 [PATCH] mm/page_alloc: free allocated PFNs if the range does not match Zi Yan
2026-06-30 2:06 ` Andrew Morton
2026-06-30 2:23 ` Zi Yan
2026-06-30 7:44 ` Vlastimil Babka (SUSE)
2026-06-30 13:39 ` David Hildenbrand (Arm)
2026-06-30 14:47 ` Lance Yang [this message]
2026-06-30 15:06 ` Zi Yan
2026-07-01 13:38 ` Zi Yan
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