On Tue, 21 May 2019 09:16:29 -0500 Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > Hmm, this may blow up with lockdep, as I believe we already have a > > locking dependency of: > > > > text_mutex -> ftrace_lock > > > > And this will reverses it. (kprobes appears to take the locks in this > > order). > > > > Perhaps have live kernel patching grab ftrace_lock? > > Where does kprobes call into ftrace with the text_mutex? I couldn't > find it. Hmm, maybe it doesn't. I was looking at the arm_kprobe_ftrace() but it doesn't call it with text_mutex(). Maybe it is fine, but we had better perform a lot of testing with lockdep on to make sure. -- Steve
