On Monday, December 3, 2018 9:39:42 AM CET Michal Hocko wrote: > On Mon 03-12-18 08:47:00, Ingo Molnar wrote: > [...] > > I reviewed the ->cred_guard_mutex code, and the mutex is held across all > > of exec() - and we always did this. > > Yes, this is something that has been pointed out during the review. Oleg > has argued that making this path freezable is really hard and that we > should be changing de_thread to sleep withtou cred_guard_mutex long term > anyway (http://lkml.kernel.org/r/20181114143705.gb13...@redhat.com). > > Failing suspend seems like a real problem while the lockdep one doesn't > really reflect any real deadlock, right? So while the patch is not > perfect it shouldn't make the situation much worse. Lockdep splat is > certainly annoying but is it any worse than a suspend failing? > > Now, I wouldn't mind to revert this because the code is really old and > we haven't seen many bug reports about failing suspend yet. But what is > the actual plan to make this work properly? Use > freezable_schedule_unsafe instead? Freezer code has some > fundamental design issues which are quite hard to get over.
I agree and we just need to look deeper into this. I had hoped that this would work since you and Oleg agreed with it, but since it doesn't, let's do a revert for now and get back to this later. Thanks, Rafael
