From: "David Hildenbrand (Arm)" <david@kernel.org>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>,
Avi Weiss <thnkslprpt@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Soheil Hassas Yeganeh <soheil@google.com>,
Arjun Roy <arjunroy@google.com>,
Eric Dumazet <edumazet@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: return -ENOMEM for page-table allocation failure in insert_pages()
Date: Thu, 30 Jul 2026 10:27:20 +0200 [thread overview]
Message-ID: <2a84e37c-407b-437c-a908-56526ce86322@kernel.org> (raw)
In-Reply-To: <amr9zoSncZguF_uu@lucifer>
On 7/30/26 09:42, Lorenzo Stoakes (ARM) wrote:
> On Thu, Jul 30, 2026 at 10:13:23AM +0300, Avi Weiss wrote:
>> walk_to_pmd() returns NULL only when p4d_alloc(), pud_alloc(), or
>> pmd_alloc() fails. These are page-table allocation failures, but
>> insert_pages() currently reports them as -EFAULT.
>>
>> Return -ENOMEM instead, consistent with the subsequent pte_alloc()
>> failure and with the single-page insert_page() path, which reports
>> failure of the same page-table allocation chain as -ENOMEM.
>>
>> Address and range validation failures in vm_insert_pages() continue to
>> return -EFAULT. Keep the later -EFAULT return for
>> pte_offset_map_lock(), which is not an allocation failure.
>>
>> Fixes: 8cd3984d81d5 ("mm/memory.c: add vm_insert_pages()")
>
> Hmm :)
>
> This isn't really a fix. Anybody relying on this returning -ENOMEM
> vs. -EFAULT here is in a state of sin anyway (unless you can point to
> specific users who are broken).
Agreed, I am missing the problem here?
--
Cheers,
David
next prev parent reply other threads:[~2026-07-30 8:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-30 7:13 [PATCH] mm: return -ENOMEM for page-table allocation failure in insert_pages() Avi Weiss
2026-07-30 7:42 ` Lorenzo Stoakes (ARM)
2026-07-30 7:43 ` Lorenzo Stoakes (ARM)
2026-07-30 8:27 ` David Hildenbrand (Arm) [this message]
2026-07-30 8:36 ` Lorenzo Stoakes (ARM)
2026-07-30 16:15 ` Andrew Morton
2026-07-30 16:27 ` Lorenzo Stoakes (ARM)
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