On Thu, Apr 16, 2020 at 03:26:23PM -0400, Steven Rostedt wrote: > On Thu, 16 Apr 2020 14:59:34 -0400 > Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote: > > > But, then will it be safe for kfree_rcu() callers from hard IRQ context to > > call this in PREEMPT_RT? That could would just break then as you cannot sleep > > in hard IRQ context even on PREEMPT_RT. > > But where in PREEMPT_RT would it be called in hard IRQ context? I am not saying that it is called now, but in the future if it is called for an interrupt that is not threaded on -rt, it would be a problem right? > Note, most interrupt handlers in PREEMPT_RT are turned into threads (except > for a very few, which shouldn't be calling kfree_rcu()). Yes those very few is what I was referring to. It also sounds like from the other thread, Paul is saying it should be allowed to be called from some contexts that are not sleepable. In those cases also the rtmutex will fall apart. thanks, - Joel
