Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756224AbaJXOeS (ORCPT ); Fri, 24 Oct 2014 10:34:18 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:58449 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751653AbaJXOeP (ORCPT ); Fri, 24 Oct 2014 10:34:15 -0400 From: "Rafael J. Wysocki" To: imre.deak@intel.com Cc: Pavel Machek , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] PM / Sleep: fix recovery during s2ram/hibernation Date: Fri, 24 Oct 2014 16:54:43 +0200 Message-ID: <1954133.lzuXy3CQTN@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1414160232.30585.36.camel@intelbox> References: <1414136593-25329-1-git-send-email-imre.deak@intel.com> <6868563.CWP0SXTtWm@vostro.rjw.lan> <1414160232.30585.36.camel@intelbox> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, October 24, 2014 05:17:12 PM Imre Deak wrote: > On Fri, 2014-10-24 at 16:04 +0200, Rafael J. Wysocki wrote: > > On Friday, October 24, 2014 10:59:09 AM Imre Deak wrote: > > > Atm, if one of the dev_pm_ops::freeze callbacks fails during the QUIESCE > > > phase we don't rollback things correctly calling the thaw and complete > > > callbacks. This could leave some devices in a suspended state in case of > > > an error during resuming from hibernation. > > > > > > Also if an asynchronous suspend_late or freeze_late callback fails > > > during the SUSPEND, FREEZE or QUIESCE phases we don't propagate the > > > corresponding error correctly, in effect ignoring the error and > > > continuing the suspend-to-ram/hibernation. During suspend-to-ram this > > > could leave some devices without a valid saved context, leading to a > > > failure to reinitialize them during resume. During hibernation this > > > could leave some devices active interfeering with the creation / > > > restoration of the hibernation image. Also this could leave the > > > corresponding devices without a valid saved context and failure to > > > reinitialize them during resume. > > > > > > v2: > > > - call dpm_resume_end() unconditionally, it's guaranteed that error > > > is non-zero > > > > > > Signed-off-by: Imre Deak > > > > These are two unrelated fixes, so please send them as two patches. > > > > > --- > > > drivers/base/power/main.c | 2 ++ > > > kernel/power/hibernate.c | 3 ++- > > > 2 files changed, 4 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > > > index 4497319..9717d5f 100644 > > > --- a/drivers/base/power/main.c > > > +++ b/drivers/base/power/main.c > > > @@ -1266,6 +1266,8 @@ int dpm_suspend_late(pm_message_t state) > > > } > > > mutex_unlock(&dpm_list_mtx); > > > async_synchronize_full(); > > > + if (!error) > > > + error = async_error; > > > if (error) { > > > suspend_stats.failed_suspend_late++; > > > dpm_save_failed_step(SUSPEND_SUSPEND_LATE); > > > > So the above will be the first fix and the below will be the second one. > > Ok. > > > > > > diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c > > > index a9dfa79..594ee7f 100644 > > > --- a/kernel/power/hibernate.c > > > +++ b/kernel/power/hibernate.c > > > @@ -502,8 +502,9 @@ int hibernation_restore(int platform_mode) > > > error = dpm_suspend_start(PMSG_QUIESCE); > > > if (!error) { > > > error = resume_target_kernel(platform_mode); > > > - dpm_resume_end(PMSG_RECOVER); > > > + BUG_ON(!error); > > > > Why BUG_ON()? Is crashing the kernel necessary here? > > I figured that this being an undefined state after restoration of a > memory image, it's better to crash than to continue and risk corrupting > some user data. So can you please add a comment explaining that new BUG_ON() along with it? > > > > > > } > > > + dpm_resume_end(PMSG_RECOVER); > > > pm_restore_gfp_mask(); > > > resume_console(); > > > pm_restore_console(); > > > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/