linux-kernel - Re: [PATCH] kho: free already restored pages when kho_restore

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Message-ID: <mafs0ikf52gxn.fsf@kernel.org>
Date: Thu, 20 Nov 2025 10:26:28 +0100
From: Pratyush Yadav <pratyush@...nel.org>
To: Pasha Tatashin <pasha.tatashin@...een.com>
Cc: Pratyush Yadav <pratyush@...nel.org>,  Andrew Morton
 <akpm@...ux-foundation.org>,  Alexander Graf <graf@...zon.com>,  Mike
 Rapoport <rppt@...nel.org>,  kexec@...ts.infradead.org,
  linux-mm@...ck.org,  linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kho: free already restored pages when
 kho_restore_vmalloc() fails

On Tue, Nov 18 2025, Pasha Tatashin wrote:

>> When kho_restore_vmalloc() fails, it frees up the pages array, but not
>> the pages it contains. These are the pages that were successfully
>> restored using kho_restore_pages(). If the failure happens when
>> restoring the pages, the ones successfully restored are leaked. If the
>> failure happens when allocating the vm_area or when mapping the pages,
>> all the pages of the preserved vmalloc buffer are leaked.
>
> Hm, I am not sure if KHO should be responsible for freeing the
> restored pages. We don't know the content of those pages, and what
> they are used for. They could be used by a hypervisor or a device.
> Therefore, it may be better to keep them leaked, and let the caller
> decide what to do next: i.e., boot into a maintenance mode, crash the
> kernel, or allow the leak until the next reboot.

Hmm, fair point. This patch can be ignored then.

-- 
Regards,
Pratyush Yadav