6.6-stable review patch. If anyone has any objections, please let me know.
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From: Zhenhua Huang quic_zhenhuah@quicinc.com
commit 89f43e1ce6f60d4f44399059595ac47f7a90a393 upstream.
Hotplugged memory can be smaller than the original memory. For example, on my target:
root@genericarmv8:~# cat /sys/kernel/debug/memblock/memory 0: 0x0000000064005000..0x0000000064023fff 0 NOMAP 1: 0x0000000064400000..0x00000000647fffff 0 NOMAP 2: 0x0000000068000000..0x000000006fffffff 0 DRV_MNG 3: 0x0000000088800000..0x0000000094ffefff 0 NONE 4: 0x0000000094fff000..0x0000000094ffffff 0 NOMAP max_pfn will affect read_page_owner. Therefore, it should first compare and then select the larger value for max_pfn.
Fixes: 8fac67ca236b ("arm64: mm: update max_pfn after memory hotplug") Cc: stable@vger.kernel.org # 6.1.x Signed-off-by: Zhenhua Huang quic_zhenhuah@quicinc.com Acked-by: David Hildenbrand david@redhat.com Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com Link: https://lore.kernel.org/r/20250321070019.1271859-1-quic_zhenhuah@quicinc.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/mm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1328,7 +1328,8 @@ int arch_add_memory(int nid, u64 start, __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); else { - max_pfn = PFN_UP(start + size); + /* Address of hotplugged memory can be smaller */ + max_pfn = max(max_pfn, PFN_UP(start + size)); max_low_pfn = max_pfn; }