map_processor() checks the cpuid value returned by acpi_map_cpuid() for -1 but acpi_map_cpuid() returns -EINVAL in case of error. As a consequence the error is ignored and the following access into percpu data with that negative cpuid results in a boot crash. This happens always when NR_CPUS/nr_cpu_ids is smaller than the number of processors listed in the ACPI tables. Use a proper error check for id < 0 so the function returns instead of trying to map CPU#(-EINVAL). Reported-by: Ingo Molnar <mingo@xxxxxxxxxx> Fixes: dc6db24d2476 ("x86/acpi: Set persistent cpuid <-> nodeid mapping when booting") Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- drivers/acpi/processor_core.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -284,7 +284,7 @@ EXPORT_SYMBOL_GPL(acpi_get_cpuid); static bool __init map_processor(acpi_handle handle, phys_cpuid_t *phys_id, int *cpuid) { - int type; + int type, id; u32 acpi_id; acpi_status status; acpi_object_type acpi_type; @@ -320,10 +320,11 @@ map_processor(acpi_handle handle, phys_c type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0; *phys_id = __acpi_get_phys_id(handle, type, acpi_id, false); - *cpuid = acpi_map_cpuid(*phys_id, acpi_id); - if (*cpuid == -1) - return false; + id = acpi_map_cpuid(*phys_id, acpi_id); + if (id < 0) + return false; + *cpuid = id; return true; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>