Re: 2.6.35.5: hibernation broken... AGAIN

From: Rafael J. Wysocki
Date: Mon Dec 06 2010 - 17:58:35 EST

On Monday, December 06, 2010, Ondrej Zary wrote:
> On Saturday 27 November 2010 21:47:01 Rafael J. Wysocki wrote:
> > On Saturday, November 27, 2010, Ondrej Zary wrote:
> > > 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@xxxxxxx> 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@xxxxxxxxxx>
> > > > > > > > > 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?
> >
> > The patch was against the current mainline.
> >
> > The one below was rebased on top of 2.6.36, so please test it with this
> > kernel.
>
> This seems to work fine (5 days and no crash).

Thanks for testing!

Rafael


> > ---
> > kernel/power/hibernate.c | 36 ++++++++++++++++++++++++++----------
> > kernel/power/power.h | 1 +
> > kernel/power/user.c | 2 ++
> > 3 files changed, 29 insertions(+), 10 deletions(-)
> >
> > Index: suspend-2.6/kernel/power/hibernate.c
> > ===================================================================
> > --- suspend-2.6.orig/kernel/power/hibernate.c
> > +++ suspend-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 noresume = 0;
> > static char resume_file[256] = CONFIG_PM_STD_PARTITION;
> > dev_t swsusp_resume_device;
> > @@ -326,7 +341,6 @@ 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)
> > @@ -338,7 +352,7 @@ 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;
> > @@ -347,7 +361,10 @@ 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. */
> > @@ -356,7 +373,10 @@ 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);
> > @@ -451,17 +471,16 @@ 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;
> > @@ -475,7 +494,6 @@ int hibernation_restore(int platform_mod
> > int hibernation_platform_enter(void)
> > {
> > int error;
> > - gfp_t saved_mask;
> >
> > if (!hibernation_ops)
> > return -ENOSYS;
> > @@ -491,7 +509,6 @@ 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)
> > @@ -535,7 +552,6 @@ 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: suspend-2.6/kernel/power/power.h
> > ===================================================================
> > --- suspend-2.6.orig/kernel/power/power.h
> > +++ suspend-2.6/kernel/power/power.h
> > @@ -49,6 +49,7 @@ 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);
> > #endif
> >
> > extern int pfn_is_nosave(unsigned long);
> > Index: suspend-2.6/kernel/power/user.c
> > ===================================================================
> > --- suspend-2.6.orig/kernel/power/user.c
> > +++ suspend-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;
> > @@ -275,6 +276,7 @@ static long snapshot_ioctl(struct file *
> > error = -EPERM;
> > break;
> > }
> > + hibernate_restore_gfp_mask();
> > error = hibernation_snapshot(data->platform_support);
> > if (!error)
> > error = put_user(in_suspend, (int __user *)arg);
>
>
>
>

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