Re: [PATCH 1/3] module: Fix livepatch/ftrace module text permissions race

From: Steven Rostedt
Date: Wed Jun 26 2019 - 10:59:16 EST

On Wed, 26 Jun 2019 16:44:45 +0200 (CEST)
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> >
> > It should be enough to fix the original problem because
> > x86 is the only architecture that calls set_all_modules_text_rw()
> > in ftrace path and supports livepatching at the same time.
> Looks correct, but I've paged out all the gory details vs. lock ordering in
> that area.

I don't believe ftrace_lock and text_mutex had an order before Petr's
initial patches. Reversing them shouldn't be an issue here. They were
basically both "leaf" mutexes (not grabbing any mutexes when they are

-- Steve