Re: 2.6.35.5: hibernation broken... AGAIN

[Ondrej Zary <linux@rainbow-software.org>]

On Saturday 27 November 2010 00:10:04 Rafael J. Wysocki wrote:
> On Friday, November 26, 2010, Ondrej Zary wrote:
> > On Thursday 18 November 2010, Hugh Dickins wrote:
> > > On Wed, 17 Nov 2010, Ondrej Zary wrote:
> > > > On Wednesday 17 November 2010 22:12:01 Rafael J. Wysocki wrote:
> > > > > On Wednesday, November 17, 2010, Andrew Morton wrote:
> > > > > > On Wed, 17 Nov 2010 21:53:52 +0100
> > > > > >
> > > > > > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
> > > > > > > On Wednesday, November 17, 2010, Ondrej Zary wrote:
> > > > > > > > Hello,
> > > > > > > > the nasty memory-corrupting hibernation bug
> > > > > > > > https://bugzilla.kernel.org/show_bug.cgi?id=15753 is back
> > > > > > > > since 2.6.35.5. 2.6.35.4 works fine, 2.6.35.5 crashes after
> > > > > > > > two days.
> > >
> > > That's distressing, for both and all of us: I'm sorry.
> > >
> > > > > > > > It seems to be caused by
> > > > > > > > b77c254d8d66e5e9aa81239fedba9f3d568097d9.
> > > > > >
> > > > > > commit b77c254d8d66e5e9aa81239fedba9f3d568097d9
> > > > > > Author: Hugh Dickins <hughd@google.com>
> > > > > > Date:   Thu Sep 9 16:38:09 2010 -0700
> > > > > >
> > > > > >     swap: prevent reuse during hibernation
> > >
> > > Embarrassing: I suspect that I've been confused, not for the first
> > > time, by the fork-like nature of hibernation and its images.
> > > I wonder if this patch below fixes it, Ondrej?
> > >
> > > (And is it kernel swsusp or user swsusp that you're using?  May not
> > > matter at all, but will help us to think more clearly about it,
> > > if the corruption remains after this patch.)
> > >
> > > Rafael, do you agree that this patch was actually required even for
> > > your original commit 452aa6999e6703ffbddd7f6ea124d3968915f3e3
> > > mm/pm: force GFP_NOIO during suspend/hibernation and resume?
> > >
> > > Or am I still just as confused?  Or if not, are there more forking
> > > places which require a similar patch?
> > >
> > > Not signing it off yet,
> > > Hugh
> >
> > Could you please do that? The patch fixes the problem.
>
> Can you check if the problem is also fixed by the patch below, please?

The patch does not apply to 2.6.35.4, 2.6.35.5 and also 2.6.36. What version 
should I test?


> Rafael
>
> ---
>  kernel/power/hibernate.c |   36 ++++++++++++++++++++++++++----------
>  kernel/power/power.h     |    1 +
>  kernel/power/user.c      |    1 +
>  3 files changed, 28 insertions(+), 10 deletions(-)
>
> Index: linux-2.6/kernel/power/hibernate.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/hibernate.c
> +++ linux-2.6/kernel/power/hibernate.c
> @@ -29,6 +29,21 @@
>  #include "power.h"
>
>
> +static gfp_t saved_gfp_mask;
> +
> +static void hibernate_restrict_gfp_mask(void)
> +{
> +	saved_gfp_mask = clear_gfp_allowed_mask(GFP_IOFS);
> +}
> +
> +void hibernate_restore_gfp_mask(void)
> +{
> +	if (saved_gfp_mask) {
> +		set_gfp_allowed_mask(saved_gfp_mask);
> +		saved_gfp_mask = 0;
> +	}
> +}
> +
>  static int nocompress = 0;
>  static int noresume = 0;
>  static char resume_file[256] = CONFIG_PM_STD_PARTITION;
> @@ -327,7 +342,6 @@ static int create_image(int platform_mod
>  int hibernation_snapshot(int platform_mode)
>  {
>  	int error;
> -	gfp_t saved_mask;
>
>  	error = platform_begin(platform_mode);
>  	if (error)
> @@ -339,7 +353,7 @@ int hibernation_snapshot(int platform_mo
>  		goto Close;
>
>  	suspend_console();
> -	saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
> +	hibernate_restrict_gfp_mask();
>  	error = dpm_suspend_start(PMSG_FREEZE);
>  	if (error)
>  		goto Recover_platform;
> @@ -348,7 +362,10 @@ int hibernation_snapshot(int platform_mo
>  		goto Recover_platform;
>
>  	error = create_image(platform_mode);
> -	/* Control returns here after successful restore */
> +	/*
> +	 * Control returns here (1) after the image has been created or the
> +	 * image creation has failed and (2) after a successful restore.
> +	 */
>
>   Resume_devices:
>  	/* We may need to release the preallocated image pages here. */
> @@ -357,7 +374,10 @@ int hibernation_snapshot(int platform_mo
>
>  	dpm_resume_end(in_suspend ?
>  		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
> -	set_gfp_allowed_mask(saved_mask);
> +
> +	if (error || !in_suspend)
> +		hibernate_restore_gfp_mask();
> +
>  	resume_console();
>   Close:
>  	platform_end(platform_mode);
> @@ -452,17 +472,16 @@ static int resume_target_kernel(bool pla
>  int hibernation_restore(int platform_mode)
>  {
>  	int error;
> -	gfp_t saved_mask;
>
>  	pm_prepare_console();
>  	suspend_console();
> -	saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
> +	hibernate_restrict_gfp_mask();
>  	error = dpm_suspend_start(PMSG_QUIESCE);
>  	if (!error) {
>  		error = resume_target_kernel(platform_mode);
>  		dpm_resume_end(PMSG_RECOVER);
>  	}
> -	set_gfp_allowed_mask(saved_mask);
> +	hibernate_restore_gfp_mask();
>  	resume_console();
>  	pm_restore_console();
>  	return error;
> @@ -476,7 +495,6 @@ int hibernation_restore(int platform_mod
>  int hibernation_platform_enter(void)
>  {
>  	int error;
> -	gfp_t saved_mask;
>
>  	if (!hibernation_ops)
>  		return -ENOSYS;
> @@ -492,7 +510,6 @@ int hibernation_platform_enter(void)
>
>  	entering_platform_hibernation = true;
>  	suspend_console();
> -	saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
>  	error = dpm_suspend_start(PMSG_HIBERNATE);
>  	if (error) {
>  		if (hibernation_ops->recover)
> @@ -536,7 +553,6 @@ int hibernation_platform_enter(void)
>   Resume_devices:
>  	entering_platform_hibernation = false;
>  	dpm_resume_end(PMSG_RESTORE);
> -	set_gfp_allowed_mask(saved_mask);
>  	resume_console();
>
>   Close:
> Index: linux-2.6/kernel/power/power.h
> ===================================================================
> --- linux-2.6.orig/kernel/power/power.h
> +++ linux-2.6/kernel/power/power.h
> @@ -52,6 +52,7 @@ static inline char *check_image_kernel(s
>  extern int hibernation_snapshot(int platform_mode);
>  extern int hibernation_restore(int platform_mode);
>  extern int hibernation_platform_enter(void);
> +extern void hibernate_restore_gfp_mask(void);
>
>  #else /* !CONFIG_HIBERNATION */
>
> Index: linux-2.6/kernel/power/user.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/user.c
> +++ linux-2.6/kernel/power/user.c
> @@ -263,6 +263,7 @@ static long snapshot_ioctl(struct file *
>  	case SNAPSHOT_UNFREEZE:
>  		if (!data->frozen || data->ready)
>  			break;
> +		hibernate_restore_gfp_mask();
>  		thaw_processes();
>  		usermodehelper_enable();
>  		data->frozen = 0;



-- 
Ondrej Zary