From: Pratyush Yadav (Google) Date: Tue, 19 May 2026 16:05:49 +0000 (+0200) Subject: kho: make sure scratch size is always aligned by CMA_MIN_ALIGNMENT_BYTES X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0e39380a7316122e1b00012b3f3cd3e318b3e7d3;p=thirdparty%2Flinux.git kho: make sure scratch size is always aligned by CMA_MIN_ALIGNMENT_BYTES When using scratch_scale, the scratch sizes are rounded up to CMA_MIN_ALIGNMENT_BYTES since they will be released as MIGRATE_CMA. This is not done when using fixed scratch sizes via command line. This can result in user specifying a size which is not aligned, and thus kernel releasing a pageblock that is only partially scratch. Do the rounding up for both cases in scratch_size_update(). Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers") Cc: stable@kernel.org Signed-off-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260519160554.2713361-1-pratyush@kernel.org Signed-off-by: Pasha Tatashin Signed-off-by: Mike Rapoport (Microsoft) --- diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index eb8abd04e7ff..4834a809985a 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -618,20 +618,30 @@ early_param("kho_scratch", kho_parse_scratch_size); static void __init scratch_size_update(void) { - phys_addr_t size; + /* + * If fixed sizes are not provided via command line, calculate them + * now. + */ + if (scratch_scale) { + phys_addr_t size; - if (!scratch_scale) - return; + size = memblock_reserved_kern_size(ARCH_LOW_ADDRESS_LIMIT, + NUMA_NO_NODE); + size = size * scratch_scale / 100; + scratch_size_lowmem = size; - size = memblock_reserved_kern_size(ARCH_LOW_ADDRESS_LIMIT, - NUMA_NO_NODE); - size = size * scratch_scale / 100; - scratch_size_lowmem = round_up(size, CMA_MIN_ALIGNMENT_BYTES); + size = memblock_reserved_kern_size(MEMBLOCK_ALLOC_ANYWHERE, + NUMA_NO_NODE); + size = size * scratch_scale / 100 - scratch_size_lowmem; + scratch_size_global = size; + } - size = memblock_reserved_kern_size(MEMBLOCK_ALLOC_ANYWHERE, - NUMA_NO_NODE); - size = size * scratch_scale / 100 - scratch_size_lowmem; - scratch_size_global = round_up(size, CMA_MIN_ALIGNMENT_BYTES); + /* + * Scratch areas are released as MIGRATE_CMA. Round them up to the right + * size. + */ + scratch_size_lowmem = round_up(scratch_size_lowmem, CMA_MIN_ALIGNMENT_BYTES); + scratch_size_global = round_up(scratch_size_global, CMA_MIN_ALIGNMENT_BYTES); } static phys_addr_t __init scratch_size_node(int nid)