linux-kernel - Re: Fwd: [v3.12-rc1] [regression] PM / hibernate: Create memory bitmaps after freezing user space

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Date:	Mon, 30 Sep 2013 19:15:13 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Ronald <ronald645@...il.com>
Cc:	linux-kernel@...r.kernel.org,
	Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: Fwd: [v3.12-rc1] [regression] PM / hibernate: Create memory bitmaps after freezing user space

On Monday, September 30, 2013 07:45:54 AM Ronald wrote:
> Yes, works as well. Just survived twe cycles with s2disk. I'm
> surprised someone else did not report this earlier btw... Because it
> looks pretty generic (i.e. not specific to a 64bit UP system).

It is a generic bug, actually.  Well, this means the user space driven
hibernation doesn't receive much testing coverage these days ...

I'll resend the patch with a proper changelog and then push it for v3.12-rc4.

Thanks,
Rafael


> 2013/9/30 Rafael J. Wysocki <rjw@...ysocki.net>:
> > On Sunday, September 29, 2013 09:22:45 AM Ronald wrote:
> >> Attached patch fixes the issue. Both methods function as they did
> >> before. Thanks for the superfast fix!
> >
> > You're welcome, it's not the final one, however.
> >
> > Can you please test the one below and report back?
> >
> > Rafael
> >
> >
> > ---
> >  kernel/power/snapshot.c |    5 ++++-
> >  kernel/power/user.c     |    8 ++++++++
> >  2 files changed, 12 insertions(+), 1 deletion(-)
> >
> > Index: linux-pm/kernel/power/snapshot.c
> > ===================================================================
> > --- linux-pm.orig/kernel/power/snapshot.c
> > +++ linux-pm/kernel/power/snapshot.c
> > @@ -743,7 +743,10 @@ int create_basic_memory_bitmaps(void)
> >         struct memory_bitmap *bm1, *bm2;
> >         int error = 0;
> >
> > -       BUG_ON(forbidden_pages_map || free_pages_map);
> > +       if (forbidden_pages_map && free_pages_map)
> > +               return 0;
> > +       else
> > +               BUG_ON(forbidden_pages_map || free_pages_map);
> >
> >         bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
> >         if (!bm1)
> > Index: linux-pm/kernel/power/user.c
> > ===================================================================
> > --- linux-pm.orig/kernel/power/user.c
> > +++ linux-pm/kernel/power/user.c
> > @@ -39,6 +39,7 @@ static struct snapshot_data {
> >         char frozen;
> >         char ready;
> >         char platform_support;
> > +       bool free_bitmaps;
> >  } snapshot_state;
> >
> >  atomic_t snapshot_device_available = ATOMIC_INIT(1);
> > @@ -82,6 +83,10 @@ static int snapshot_open(struct inode *i
> >                 data->swap = -1;
> >                 data->mode = O_WRONLY;
> >                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
> > +               if (!error) {
> > +                       error = create_basic_memory_bitmaps();
> > +                       data->free_bitmaps = !error;
> > +               }
> >                 if (error)
> >                         pm_notifier_call_chain(PM_POST_RESTORE);
> >         }
> > @@ -111,6 +116,8 @@ static int snapshot_release(struct inode
> >                 pm_restore_gfp_mask();
> >                 free_basic_memory_bitmaps();
> >                 thaw_processes();
> > +       } else if (data->free_bitmaps) {
> > +               free_basic_memory_bitmaps();
> >         }
> >         pm_notifier_call_chain(data->mode == O_RDONLY ?
> >                         PM_POST_HIBERNATION : PM_POST_RESTORE);
> > @@ -231,6 +238,7 @@ static long snapshot_ioctl(struct file *
> >                         break;
> >                 pm_restore_gfp_mask();
> >                 free_basic_memory_bitmaps();
> > +               data->free_bitmaps = false;
> >                 thaw_processes();
> >                 data->frozen = 0;
> >                 break;
> >
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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