Re: [PATCH v4 4/4] livepatch/module: remove livepatch module notifier

From: Rusty Russell
Date: Mon Feb 29 2016 - 21:06:20 EST

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>