On Wednesday, April 30, 2014 03:46:33 PM Lan Tianyu wrote: > According commit d640113fe(ACPI: processor: fix acpi_get_cpuid for UP > processor), Bios may not provide _MAT or MADT tables and acpi_get_apicid() > always returns -1. For these cases, original code will pass apic_id with > vaule of -1 to acpi_map_cpuid() and it will check the acpi_id. If acpi_id > is equal to zero, ignores apic_id and return zero for CPU0. > > Commit b981513(ACPI / scan: bail out early if failed to parse APIC > ID for CPU) changed the behavior. Return ENODEV when find apic_id is > less than zero after calling acpi_get_apicid(). This causes acpi-cpufreq > driver fails to be loaded on some machines. This patch is to fix it. > > Reference:https://bugzilla.kernel.org/show_bug.cgi?id=73781 > Cc: stable@xxxxxxxxxxxxxxx v3.14 > Reported-and-tested-by: KATO Hiroshi <katoh@xxxxxxxxxxxx> > Reported-and-tested-by: Stuart Foster <smf.linux@xxxxxxxxxxxx> > Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx> > --- > Change since V1: > Add a check for pr->apic_id in the acpi_processor_hotadd_init() > to avoid invalid memory access. Queued up for the next pull request, thanks! > drivers/acpi/acpi_processor.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > index c29c2c3..b06f5f5 100644 > --- a/drivers/acpi/acpi_processor.c > +++ b/drivers/acpi/acpi_processor.c > @@ -170,6 +170,9 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr) > acpi_status status; > int ret; > > + if (pr->apic_id == -1) > + return -ENODEV; > + > status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); > if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT)) > return -ENODEV; > @@ -260,10 +263,8 @@ static int acpi_processor_get_info(struct acpi_device *device) > } > > apic_id = acpi_get_apicid(pr->handle, device_declaration, pr->acpi_id); > - if (apic_id < 0) { > + if (apic_id < 0) > acpi_handle_debug(pr->handle, "failed to get CPU APIC ID.\n"); > - return -ENODEV; > - } > pr->apic_id = apic_id; > > cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id); > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
