linux-kernel - Re: [PATCH] kho: free chunks using free

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Message-ID: <aR1uWvLu5Hlneppp@kernel.org>
Date: Wed, 19 Nov 2025 09:14:34 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Pratyush Yadav <pratyush@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Alexander Graf <graf@...zon.com>,
	Pasha Tatashin <pasha.tatashin@...een.com>,
	David Matlack <dmatlack@...gle.com>, kexec@...ts.infradead.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kho: free chunks using free_page() instead of kfree()

On Tue, Nov 18, 2025 at 07:22:16PM +0100, Pratyush Yadav wrote:
> Before commit fa759cd75bce5 ("kho: allocate metadata directly from the
> buddy allocator"), the chunks were allocated from the slab allocator
> using kzalloc(). Those were rightly freed using kfree().
> 
> When the commit switched to using the buddy allocator directly, it
> missed updating kho_mem_ser_free() to use free_page() instead of
> kfree().
> 
> Fixes: fa759cd75bce5 ("kho: allocate metadata directly from the buddy allocator")
> Signed-off-by: Pratyush Yadav <pratyush@...nel.org>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@...nel.org>

> ---
> 
> Notes:
>     Commit 73976b0f7cefe ("kho: remove abort functionality and support state
>     refresh") made this bug easier to trigger by providing a deterministic
>     method to trigger freeing of the chunks.
> 
>  kernel/liveupdate/kexec_handover.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
> index 515339fa526e0..6497fe68c2d24 100644
> --- a/kernel/liveupdate/kexec_handover.c
> +++ b/kernel/liveupdate/kexec_handover.c
> @@ -360,7 +360,7 @@ static void kho_mem_ser_free(struct khoser_mem_chunk *first_chunk)
>  		struct khoser_mem_chunk *tmp = chunk;
>  
>  		chunk = KHOSER_LOAD_PTR(chunk->hdr.next);
> -		kfree(tmp);
> +		free_page((unsigned long)tmp);
>  	}
>  }
>  
> 
> base-commit: f0bfdc2b69f5c600b88ee484c01b213712c63d94
> prerequisite-patch-id: f54df1de9bdcb4fe396940cdcc578f5adcc9397c
> prerequisite-patch-id: 800ec910c37120fd77aff1fad8ec10daaeaeddb1
> -- 
> 2.47.3
> 

-- 
Sincerely yours,
Mike.