Hi Tianyu, Found another issue at the second glance. In case of x2apic, "if (apic_id < 0)" should be replaced by "if (apic_id == -1)" for safety. Best Regards! Gerry On 2014/4/30 13:08, Jiang Liu wrote: > Hi Tianyu, > With the suggested fix, we still need to protect > acpi_processor_hotadd_init() when pr->apic_id is -1, > otherwise it may cause invalid memory access. > > Best Regards! > Gerry > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > index c29c2c3ec0ad..e17befc54c34 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 < 0) > + return -ENODEV; > + > status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); > if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT)) > return -ENODEV; > > > On 2014/4/30 11:10, 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> >> --- >> drivers/acpi/acpi_processor.c | 4 +--- >> 1 file changed, 1 insertion(+), 3 deletions(-) >> >> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c >> index c29c2c3..d55b603 100644 >> --- a/drivers/acpi/acpi_processor.c >> +++ b/drivers/acpi/acpi_processor.c >> @@ -260,10 +260,8 @@ 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); >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- 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
