On Wed, May 25, 2016 at 03:16:40PM +0200, Peter Zijlstra wrote: > On Tue, May 24, 2016 at 03:52:28PM -0700, Andy Lutomirski wrote: > > + struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer); > > > > + if (!buffer || buffer->nesting >= 4) > > return NULL; > > This is buggy fwiw; you need to unconditionally increment > buffer->nesting to match the unconditional decrement. > > Otherwise 5 'increments' and 5 decrements will land you at -1.
Urgh, never mind me; if you don't dec when returning NULL this should work out fine. My head really aint working right today.
