From 7cdcdab1a660bbe9f98bf1591c048ce7ccee59e0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 13 Feb 2024 22:05:57 +0100 Subject: [PATCH] x86/cpu/topology: Reject unknown APIC IDs on ACPI hotplug The topology bitmaps track all possible APIC IDs which have been registered during enumeration. As sizing and further topology information is going to be derived from these bitmaps, reject attempts to hotplug an APIC ID which was not registered during enumeration. Signed-off-by: Thomas Gleixner Tested-by: Michael Kelley Tested-by: Sohil Mehta Link: https://lore.kernel.org/r/20240213210252.462231229@linutronix.de --- arch/x86/kernel/cpu/topology.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c index c67120657e556..a6d045b15ebdc 100644 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -272,6 +272,10 @@ int topology_hotplug_apic(u32 apic_id, u32 acpi_id) if (apic_id >= MAX_LOCAL_APIC) return -EINVAL; + /* Reject if the APIC ID was not registered during enumeration. */ + if (!test_bit(apic_id, apic_maps[TOPO_SMT_DOMAIN].map)) + return -ENODEV; + cpu = topo_lookup_cpuid(apic_id); if (cpu < 0) { if (topo_info.nr_assigned_cpus >= nr_cpu_ids) -- 2.30.2