On 2014年04月30日 13:16, Jiang Liu wrote: > 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. Hi Jiang: Thanks for suggestion. I will update soon. > 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/ >> -- Best regards Tianyu Lan -- 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
