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authorThomas Gleixner <tglx@linutronix.de>2024-04-08 15:22:01 +0200
committerThomas Gleixner <tglx@linutronix.de>2024-04-10 15:31:38 +0200
commita9025cd1c673a8d6eefc79d911075b8b452eba8f (patch)
tree8c4efc2151ed13d080156f9e4917b0180a6716eb /arch
parent04f4230e2f86a4e961ea5466eda3db8c1762004d (diff)
x86/topology: Don't update cpu_possible_map in topo_set_cpuids()
topo_set_cpuids() updates cpu_present_map and cpu_possible map. It is invoked during enumeration and "physical hotplug" operations. In the latter case this results in a kernel crash because cpu_possible_map is marked read only after init completes. There is no reason to update cpu_possible_map in that function. During enumeration cpu_possible_map is not relevant and gets fully initialized after enumeration completed. On "physical hotplug" the bit is already set because the kernel allows only CPUs to be plugged which have been enumerated and associated to a CPU number during early boot. Remove the bogus update of cpu_possible_map. Fixes: 0e53e7b656cf ("x86/cpu/topology: Sanitize the APIC admission logic") Reported-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/87ttkc6kwx.ffs@tglx
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/topology.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index aaca8d235dc2..d17c9b71eb4a 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -123,7 +123,6 @@ static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id)
early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;
early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
#endif
- set_cpu_possible(cpu, true);
set_cpu_present(cpu, true);
}
@@ -210,7 +209,11 @@ static __init void topo_register_apic(u32 apic_id, u32 acpi_id, bool present)
topo_info.nr_disabled_cpus++;
}
- /* Register present and possible CPUs in the domain maps */
+ /*
+ * Register present and possible CPUs in the domain
+ * maps. cpu_possible_map will be updated in
+ * topology_init_possible_cpus() after enumeration is done.
+ */
for (dom = TOPO_SMT_DOMAIN; dom < TOPO_MAX_DOMAIN; dom++)
set_bit(topo_apicid(apic_id, dom), apic_maps[dom].map);
}