Re: [linux-pm] [2.6.30-rc1-git2 regressions] Hibernation broken and (minor but annoying) audio problem

Rafael J. Wysocki
2009-04-11T00:06:51Z

[Sorry for having to switch the From address, my MTA has just decided to break.]

On Friday 10 April 2009, Linus Torvalds wrote:
>
> On Fri, 10 Apr 2009, Rafael J. Wysocki wrote:
> >
> > I've just verified that the resume-after-hibernation issue goes away after
> > reverting commit 9710794383ee5008d67f1a6613a4717bf6de47bc
> > (async: remove the temporary (2.6.29) "async is off by default" code) , so it
> > is async-related.
>
> Arjan? Clearly all the necessary fixes weren't found..
>
> There _is_ a module loading problem wrt initmem - I think you found that
> and we added a hack for it for the ACPI battery driver. I wonder if we're
> hitting a similar issue now with module discovery: modules that use
> "async_schedule()" to do their discovery asynchronously are now not
> necessarily fully "done" when the module is loaded.
>
> And so, anything that expected the devices to be available after module
> load (like they used to) would be screwed.
>
> IOW, maybe something like the totally untested patch appended here (that
> should also allow us to make the ACPI battery code to go back to using
> __init).

I tested it and it worked.

> As usual, I'm not using modules, so what do I know.
>
> > The audio issue still remains after the revert, so it is really different.
>
> Ok, probably something from Takashi..

This one is only reproducible in one out of three attempts on the average.
I tried to bisect, but it went to nowhere.

Thanks,
Rafael

> ---
> kernel/module.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 05f014e..e797812 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2388,6 +2388,9 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
> blocking_notifier_call_chain(&module_notify_list,
> MODULE_STATE_LIVE, mod);
>
> + /* We need to finish all async code before the module init sequence is done */
> + async_synchronize_full();
> +
> mutex_lock(&module_mutex);
> /* Drop initial reference. */
> module_put(mod);
>