From mboxrd@z Thu Jan 1 00:00:00 1970 From: yakui.zhao@intel.com Subject: [PATCH 1/2] ACPI: Check the returned value of set_cpus_allowed_ptr before T-state operation Date: Mon, 10 Jan 2011 16:35:44 +0800 Message-ID: <1294648545-32193-1-git-send-email-yakui.zhao@intel.com> Return-path: Received: from mga09.intel.com ([134.134.136.24]:45855 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751820Ab1AJIeH (ORCPT ); Mon, 10 Jan 2011 03:34:07 -0500 Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: lenb@kernel.org Cc: linux-acpi@vger.kernel.org, Zhao Yakui From: Zhao Yakui Now before it executes the T-state operation on one CPU, it will try to migrate to the target CPU. Especially this is required on the system that uses the MSR_IA32_THERMAL_CONTROL register to switch T-state. But unfortunately it doesn't check whether the migration is successful or not. In such case we will get/set the incorrect T-state on the offline CPU as it fails in the migration to the offline CPU. Signed-off-by: Zhao Yakui --- drivers/acpi/processor_throttling.c | 24 +++++++++++++++++++++--- 1 files changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c index ff36327..ffc859c 100644 --- a/drivers/acpi/processor_throttling.c +++ b/drivers/acpi/processor_throttling.c @@ -876,7 +876,11 @@ static int acpi_processor_get_throttling(struct acpi_processor *pr) */ cpumask_copy(saved_mask, ¤t->cpus_allowed); /* FIXME: use work_on_cpu() */ - set_cpus_allowed_ptr(current, cpumask_of(pr->id)); + if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) { + /* Can't migrate to the target pr->id CPU. Exit */ + free_cpumask_var(saved_mask); + return -ENODEV; + } ret = pr->throttling.acpi_processor_get_throttling(pr); /* restore the previous state */ set_cpus_allowed_ptr(current, saved_mask); @@ -1051,6 +1055,14 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, return -ENOMEM; } + if (cpu_is_offline(pr->id)) { + /* + * the cpu pointed by pr->id is offline. Unnecessary to change + * the throttling state any more. + */ + return -ENODEV; + } + cpumask_copy(saved_mask, ¤t->cpus_allowed); t_state.target_state = state; p_throttling = &(pr->throttling); @@ -1074,7 +1086,11 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, */ if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) { /* FIXME: use work_on_cpu() */ - set_cpus_allowed_ptr(current, cpumask_of(pr->id)); + if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) { + /* Can't migrate to the pr->id CPU. Exit */ + ret = -ENODEV; + goto exit; + } ret = p_throttling->acpi_processor_set_throttling(pr, t_state.target_state, force); } else { @@ -1106,7 +1122,8 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, } t_state.cpu = i; /* FIXME: use work_on_cpu() */ - set_cpus_allowed_ptr(current, cpumask_of(i)); + if (set_cpus_allowed_ptr(current, cpumask_of(i))) + continue; ret = match_pr->throttling. acpi_processor_set_throttling( match_pr, t_state.target_state, force); @@ -1126,6 +1143,7 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, /* restore the previous state */ /* FIXME: use work_on_cpu() */ set_cpus_allowed_ptr(current, saved_mask); +exit: free_cpumask_var(online_throttling_cpus); free_cpumask_var(saved_mask); return ret; -- 1.5.4.5