From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753421AbdCFMzB (ORCPT ); Mon, 6 Mar 2017 07:55:01 -0500 Received: from mail-pg0-f66.google.com ([74.125.83.66]:34225 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753144AbdCFMyo (ORCPT ); Mon, 6 Mar 2017 07:54:44 -0500 From: Sergey Senozhatsky X-Google-Original-From: Sergey Senozhatsky To: Steven Rostedt , Petr Mladek Cc: Andrew Morton , Linus Torvalds , Peter Zijlstra , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [RFC][PATCH 3/4] kernel, power: disable printk_kthread in unsafe places Date: Mon, 6 Mar 2017 21:45:53 +0900 Message-Id: <20170306124554.828-4-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170306124554.828-1-sergey.senozhatsky@gmail.com> References: <20170306124554.828-1-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's not always possible/safe to wake_up() printk kernel thread. For example, late suspend/early resume may printk() while timekeeping is not initialized yet, so calling into the scheduler may result in recursive warnings. Thus we need printk() to operate in old mode there and attempt to immediately flush pending kernel message to the console. This patch adds console_printing_thread_off/on sections. Signed-off-by: Sergey Senozhatsky --- kernel/kexec_core.c | 4 ++++ kernel/power/hibernate.c | 8 ++++++++ kernel/power/suspend.c | 4 ++++ 3 files changed, 16 insertions(+) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index bfe62d5b3872..b40fba31150c 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1496,6 +1496,8 @@ int kernel_kexec(void) goto Unlock; } + console_printing_thread_off(); + #ifdef CONFIG_KEXEC_JUMP if (kexec_image->preserve_context) { lock_system_sleep(); @@ -1565,6 +1567,8 @@ int kernel_kexec(void) } #endif + console_printing_thread_on(); + Unlock: mutex_unlock(&kexec_mutex); return error; diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index a8b978c35a6a..15634841ccc6 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -502,6 +502,7 @@ int hibernation_restore(int platform_mode) { int error; + console_printing_thread_off(); pm_prepare_console(); suspend_console(); pm_restrict_gfp_mask(); @@ -519,6 +520,7 @@ int hibernation_restore(int platform_mode) pm_restore_gfp_mask(); resume_console(); pm_restore_console(); + console_printing_thread_on(); return error; } @@ -542,6 +544,7 @@ int hibernation_platform_enter(void) goto Close; entering_platform_hibernation = true; + console_printing_thread_off(); suspend_console(); error = dpm_suspend_start(PMSG_HIBERNATE); if (error) { @@ -589,6 +592,7 @@ int hibernation_platform_enter(void) entering_platform_hibernation = false; dpm_resume_end(PMSG_RESTORE); resume_console(); + console_printing_thread_on(); Close: hibernation_ops->end(); @@ -692,6 +696,7 @@ int hibernate(void) goto Unlock; } + console_printing_thread_off(); pm_prepare_console(); error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); if (error) { @@ -759,6 +764,7 @@ int hibernate(void) Exit: __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL); pm_restore_console(); + console_printing_thread_on(); atomic_inc(&snapshot_device_available); Unlock: unlock_system_sleep(); @@ -868,6 +874,7 @@ static int software_resume(void) goto Unlock; } + console_printing_thread_off(); pm_prepare_console(); error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); if (error) { @@ -884,6 +891,7 @@ static int software_resume(void) Finish: __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); pm_restore_console(); + console_printing_thread_on(); atomic_inc(&snapshot_device_available); /* For success case, the suspend path will release the lock */ Unlock: diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 15e6baef5c73..7c6e228b7de4 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -433,6 +433,7 @@ int suspend_devices_and_enter(suspend_state_t state) if (!sleep_state_supported(state)) return -ENOSYS; + console_printing_thread_off(); error = platform_suspend_begin(state); if (error) goto Close; @@ -462,6 +463,7 @@ int suspend_devices_and_enter(suspend_state_t state) Close: platform_resume_end(state); + console_printing_thread_on(); return error; Recover_platform: @@ -520,6 +522,7 @@ static int enter_state(suspend_state_t state) #endif pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]); + console_printing_thread_off(); pm_suspend_clear_flags(); error = suspend_prepare(state); if (error) @@ -537,6 +540,7 @@ static int enter_state(suspend_state_t state) Finish: pr_debug("PM: Finishing wakeup.\n"); suspend_finish(); + console_printing_thread_on(); Unlock: mutex_unlock(&pm_mutex); return error; -- 2.12.0