On Wed 2016-07-13 22:44:24, Rafael J. Wysocki wrote:
> On Wed, Jul 13, 2016 at 10:26 PM, Pavel Machek <[email protected]> wrote:
> > On Wed 2016-07-13 22:04:27, Rafael J. Wysocki wrote:
> >> On Wed, Jul 13, 2016 at 7:01 PM, Pavel Machek <[email protected]> wrote:
> >> > Hi!
> >> >
> >> >> >>and then swapon the swap device, and do a testing. This should be
> >> >> >>safer?
> >> >> >Yeah, that's the way. Read-only root is other option.
> >> >> >
> >> >> >>>I guess updating documentation would be welcome from my side,
> >> >> >>>otherwise it should be ok.
> >> >> >>OK, I'll update the documents.
> >> >> >Just add fat warning into the documentation.
> >> >> OK.
> >> >
> >> > Actually... If you could add
> >> >
> >> > printk(KERN_ALERT "Hibernation image written. If you have any
> >> > filesystems mounted read-write and attempt to resume, you'll corrupt
> >> > your data. To prevent that, remove the hibernation image.\n")
> >> >
> >> > ...I guess that would save someone's filesystem. (Yes, very high
> >> > loglevel. If you attempt to do this from anything else then singleuser
> >> > or initrd, you are asking for problems, so... lets make sure user sees
> >> > it.)
> >>
> >> Please see the new version of this patch:
> >> https://patchwork.kernel.org/patch/9226837/
> >
> > New version changes nothing, right? You still need to be sure
> > filesystems are not mounted r/w. So I would still like to see printk()
> > with warning.
>
> It shouldn't matter how they are mounted, because the contents of
> persistent storage don't change.
@@ -721,6 +724,9 @@ int hibernate(void)
atomic_inc(&snapshot_device_available);
Unlock:
unlock_system_sleep();
+ if (snapshot_test)
+ software_resume();
+
return error;
}
Aha, I see, immediate wakeup here. Makes sense. ... ...
No.
AFAICT, freezer is used in hibernation_snapshot, which means at
Unlock:, kernel threads are running; software_resume() freezes them
again, but they had chance to run and potentially corrupt the
persistent storage... right?
Pavel
--
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