On Tue, 21 May 2019 11:42:27 -0500 Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > Hm. I suppose using ftrace_lock might be less risky since that lock is > only used internally by ftrace (up until now). But I think it would > also make less sense because the text_mutex is supposed to protect code > patching. And presumably ftrace_lock is supposed to be ftrace-specific. > > Here's the latest patch, still using text_mutex. I added some lockdep > assertions to ensure the permissions toggling functions are always > called with text_mutex. It's running through 0-day right now. I can > try to run it through various tests with CONFIG_LOCKDEP. Yeah, text_mutex probably does make more sense. ftrace_mutex was around before text_mutex as ftrace was the first one to do the runtime patching (after boot has finished). It wasn't until we introduced text_poke that we decided to create the text_mutex locking as well. > > > From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > Subject: [PATCH] livepatch: Fix ftrace module text permissions race Thanks, I'll try to find some time to test this as well. -- Steve
