From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755789Ab2GaEvS (ORCPT ); Tue, 31 Jul 2012 00:51:18 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:48901 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755748Ab2GaEvL (ORCPT ); Tue, 31 Jul 2012 00:51:11 -0400 Message-Id: <20120731044316.272290483@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Tue, 31 Jul 2012 05:43:41 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "Srivatsa S. Bhat" , "Rafael J. Wysocki" Subject: [ 31/73] ftrace: Disable function tracing during suspend/resume and hibernation, again In-Reply-To: <20120731044310.013763753@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Srivatsa S. Bhat" commit 443772d408a25af62498793f6f805ce3c559309a upstream. If function tracing is enabled for some of the low-level suspend/resume functions, it leads to triple fault during resume from suspend, ultimately ending up in a reboot instead of a resume (or a total refusal to come out of suspended state, on some machines). This issue was explained in more detail in commit f42ac38c59e0a03d (ftrace: disable tracing for suspend to ram). However, the changes made by that commit got reverted by commit cbe2f5a6e84eebb (tracing: allow tracing of suspend/resume & hibernation code again). So, unfortunately since things are not yet robust enough to allow tracing of low-level suspend/resume functions, suspend/resume is still broken when ftrace is enabled. So fix this by disabling function tracing during suspend/resume & hibernation. Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki Signed-off-by: Ben Hutchings --- kernel/power/hibernate.c | 6 ++++++ kernel/power/suspend.c | 3 +++ 2 files changed, 9 insertions(+) --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -367,6 +367,7 @@ int hibernation_snapshot(int platform_mo } suspend_console(); + ftrace_stop(); pm_restrict_gfp_mask(); error = dpm_suspend(PMSG_FREEZE); if (error) @@ -392,6 +393,7 @@ int hibernation_snapshot(int platform_mo if (error || !in_suspend) pm_restore_gfp_mask(); + ftrace_start(); resume_console(); dpm_complete(msg); @@ -496,6 +498,7 @@ int hibernation_restore(int platform_mod pm_prepare_console(); suspend_console(); + ftrace_stop(); pm_restrict_gfp_mask(); error = dpm_suspend_start(PMSG_QUIESCE); if (!error) { @@ -503,6 +506,7 @@ int hibernation_restore(int platform_mod dpm_resume_end(PMSG_RECOVER); } pm_restore_gfp_mask(); + ftrace_start(); resume_console(); pm_restore_console(); return error; @@ -529,6 +533,7 @@ int hibernation_platform_enter(void) entering_platform_hibernation = true; suspend_console(); + ftrace_stop(); error = dpm_suspend_start(PMSG_HIBERNATE); if (error) { if (hibernation_ops->recover) @@ -572,6 +577,7 @@ int hibernation_platform_enter(void) Resume_devices: entering_platform_hibernation = false; dpm_resume_end(PMSG_RESTORE); + ftrace_start(); resume_console(); Close: --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include "power.h" @@ -220,6 +221,7 @@ int suspend_devices_and_enter(suspend_st goto Close; } suspend_console(); + ftrace_stop(); suspend_test_start(); error = dpm_suspend_start(PMSG_SUSPEND); if (error) { @@ -239,6 +241,7 @@ int suspend_devices_and_enter(suspend_st suspend_test_start(); dpm_resume_end(PMSG_RESUME); suspend_test_finish("resume devices"); + ftrace_start(); resume_console(); Close: if (suspend_ops->end)