From: Luiz Capitulino <luizcap@redhat.com>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>,
"Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <liam@infradead.org>,
Jann Horn <jannh@google.com>, Pedro Falcato <pfalcato@suse.de>,
David Hildenbrand <david@kernel.org>,
Jakub Matena <matenajakub@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [REGRESSION] mremap() fails VMA expansion when VM_MIXEDMAP is set
Date: Fri, 23 Oct 2026 08:16:26 -0400 [thread overview]
Message-ID: <50545ab3-bf06-456d-8d14-2536f90f6f65@redhat.com> (raw)
In-Reply-To: <atsYe34Qvw5oUDMZ@gremlin>
On 10/23/26 4:19 AM, Lorenzo Stoakes (ARM) wrote:
> On Fri, Oct 23, 2026 at 09:16:12AM +0200, Vlastimil Babka (SUSE) wrote:
>> On 10/23/26 04:31, Luiz Capitulino wrote:
>
>>> This regression was introduced in v6.1 by commit ca3d76b0aa80 ("mm: add merging
>>> after mremap resize"). This commit changed mremap() to use vma_merge() instead
>>> of vma_adjust() for the expansion case. However, vma_merge() returns NULL for
>>> a VMA that has any of the VM_SPECIAL flags set.
>>
>> Hi,
>>
>> 6.1 was a rather long time ago. How was it discovered just now? I.e. what
>> use case broke by the change and prompted creating the reproducer?
>>
>> Vlastimil
>> Thanks,
>
> Thanks, I have the same questions :)
>
> Do always include that kind of information and whether it was an LLM-discovered
> thing or whether you had an actual workload that was impacted, etc.
Will do the next time, I claried the use-case in my response to
Vlastimil.
>
> --
> Cheers, Lorenzo
next prev parent reply other threads:[~2026-10-23 12:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-23 2:31 Luiz Capitulino
2026-10-23 7:16 ` Vlastimil Babka (SUSE)
2026-10-23 8:19 ` Lorenzo Stoakes (ARM)
2026-10-23 12:16 ` Luiz Capitulino [this message]
2026-10-23 12:13 ` Luiz Capitulino
2026-10-23 13:00 ` Pedro Falcato
2026-10-23 8:18 ` Lorenzo Stoakes (ARM)
2026-10-23 12:15 ` Luiz Capitulino
2026-10-23 14:28 ` Lorenzo Stoakes (ARM)
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