Messages in this thread |  | | Date | Wed, 5 Nov 2008 18:08:36 +0100 | From | Ingo Molnar <> | Subject | Re: bug: ftrace & lockdep badness |
| |
* Steven Rostedt <rostedt@goodmis.org> wrote:
> > On Wed, 5 Nov 2008, Ingo Molnar wrote: > > > > > * Steven Rostedt <rostedt@goodmis.org> wrote: > > > > > This is the type of problems we deal with when we have the tracer > > > tracing lockdep code at the same time the lockdep code is checking > > > the tracer. > > > > ok ... you are right, i guess we need to go back to raw locks after > > all? > > I do like the fact that lockdep checks it too. But there's times > that we can not do that. > > Perhaps we can do something in between. > > Make a rb_spin_lock macro inside ring_buffer.c that can be either a > spin_lock or a raw_spin_lock. There are some tracers that must have > this as a raw (function trace, irqsoff and preemptoff), but the rest > should be fine. We can make it where the rb_spin_lock is a raw lock > when any of those three tracers are configured, and make it into a > normal lock when they are not. > > This way we can still test the integrity of the ring_buffer for > other tracers. We just need to be careful when we are using function > tracing or irqs/preempt off tracing. But we need to be careful with > those anyway.
i'd rather we not complicate this anymore and just go for raw locks unconditionally - or no raw locks unconditionally.
Ingo
|  |