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From: "Jose A. Perez de Azpillaga" <azpijr@gmail.com>
To: "Mike Rapoport (Microsoft)" <rppt@kernel.org>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Chen Pei <cp0613@linux.alibaba.com>,
	George Guo <guodongtai@kylinos.cn>,
	Kexin Liu <liukexin@kylinos.cn>,
	Sourabh Jain <sourabhjain@linux.ibm.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH v2 1/3] kho: walk bootmem areas in address order
Date: Wed, 4 Nov 2026 23:14:21 +0100	[thread overview]
Message-ID: <ee08889d-4cbf-46e7-b6e5-3cf4fa8cfc6c@gmail.com> (raw)
In-Reply-To: <20261104-kho-bootmem-sizing-v2-1-b0d1a834780f@kernel.org>

On 11/4/26 5:50 PM, Mike Rapoport (Microsoft) wrote:
> kexec_add_buffer() users may depend on the order in which memory holes are
> searched. For instance, arm64 places the kernel bottom-up and then
> requires the DTB to be above the kernel.
> 
> kho_walk_bootmem() walks the bootmem areas in the order they were
> reserved, so if the kernel lands in a small area at the top of the memory
> there is no room left for the DTB and kexec fails. For example, on an
> arm64 VM with 2G of RAM and kho_bootmem=8M,64M,64M, the lowmem area is
> reserved first at the top of the memory, the kernel image takes most of
> it and kexec fails with
> 
>   kexec_file(Image): Could not find any suitable kernel location!
> 
> Sort the bootmem areas by address and walk them in ascending order, or in
> descending order for top-down searches, like kexec_walk_resources() does.
> 
> Fixes: 3bdecc3c93f9 ("kexec: add KHO support to kexec file loads")
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Jose A. Perez de Azpillaga <azpijr@gmail.com>

-- 
cheers,
jose a. p-a


  parent reply	other threads:[~2026-11-04 22:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-04 16:50 [PATCH v2 0/3] kho: fix bootmem sizing Mike Rapoport (Microsoft)
2026-11-04 16:50 ` [PATCH v2 1/3] kho: walk bootmem areas in address order Mike Rapoport (Microsoft)
2026-11-04 18:57   ` Pasha Tatashin
2026-11-04 22:14   ` Jose A. Perez de Azpillaga [this message]
2026-11-04 16:50 ` [PATCH v2 2/3] kho: skip zero-sized lowmem and global bootmem areas Mike Rapoport (Microsoft)
2026-11-04 18:57   ` Pasha Tatashin
2026-11-04 22:17   ` Jose A. Perez de Azpillaga
2026-11-04 16:50 ` [PATCH v2 3/3] kho: fix bootmem sizing Mike Rapoport (Microsoft)
2026-11-04 18:57   ` Pasha Tatashin
2026-11-05  9:26     ` Mike Rapoport
2026-11-04 22:17   ` Jose A. Perez de Azpillaga

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