Re: livepatch/module: remove livepatch module notifier

[Jessica Yu]

+++ Rusty Russell [29/02/16 11:00 +1030]:
> Jiri Kosina <jikos@xxxxxxxxxx> writes:
> > On Wed, 10 Feb 2016, Rusty Russell wrote:
> >
> > > > Remove the livepatch module notifier in favor of directly enabling and
> > > > disabling patches to modules in the module loader. Hard-coding the
> > > > function calls ensures that ftrace_module_enable() is run before
> > > > klp_module_coming() during module load, and that klp_module_going() is
> > > > run before ftrace_release_mod() during module unload. This way, ftrace
> > > > and livepatch code is run in the correct order during the module
> > > > load/unload sequence without dependence on the module notifier call chain.
> > > >
> > > > This fixes a notifier ordering issue in which the ftrace module notifier
> > > > (and hence ftrace_module_enable()) for coming modules was being called
> > > > after klp_module_notify(), which caused livepatch modules to initialize
> > > > incorrectly.
> > >
> > > Without a Fixes: line, it's not absolutely clear whether this needs
> > > CC:stable, needs to go to Linus now, or can wait for the next merge
> > > window.
> > >
> > > I *think* you want all four merged this merge window, and 3 and 4 are
> > > required to fix a regression introduced since 4.4...
> >
> > Your understanding is correct; #3 and #4 are needed to fix a 4.4
> > regression. It makes sense for the whole lot go to together, but for #1
> > and #2 I absolutely need your Ack before I take it to my tree, as I don't
> > want to be merging this behind your back.
> >
> > Once you Ack #1 and #2, I plan to take this to Linus immediately so that
> > we avoid doing these changes as very last minute.
>
> Sorry Jiri, I am on paternity leave.  Am happy with all these patches;
> please use your best judgement:
>
> Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

Thanks Rusty. No worries, we got the regression out of the way already. :-)

Jiri, I'll resend the remaining 3 patches in the series separately,
since we've merged the ftrace patch already.

Jessica