----- On Apr 7, 2017, at 2:10 PM, rostedt [email protected] wrote: > From: "Steven Rostedt (VMware)" <[email protected]> > > Stack tracing discovered that there's a small location inside the RCU > infrastructure where calling rcu_irq_enter() does not work. As trace events > use rcu_irq_enter() it must make sure that it is functionable. A check > against rcu_irq_enter_disabled() is added with a WARN_ON_ONCE() as no trace > event should ever be used in that part of RCU. If the warning is triggered, > then the trace event is ignored. > > Link: http://lkml.kernel.org/r/[email protected] > > Cc: Mathieu (making code boring) Desnoyers <[email protected]> > Signed-off-by: Steven Rostedt (VMware) <[email protected]> > --- > > Mathieu, > > There! Are you now satisfied?
Since you reversed the boolean logic from my proposal, perhaps rename the "rcucheck" argument to "rcudisabled" to reflect the logic swap ? Other than that: Acked-by: Mathieu Desnoyers <[email protected]> Thanks, Mathieu > > > > include/linux/tracepoint.h | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h > index f72fcfe..7f98d50 100644 > --- a/include/linux/tracepoint.h > +++ b/include/linux/tracepoint.h > @@ -128,7 +128,7 @@ extern void syscall_unregfunc(void); > * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just > * "void *data", where as the DECLARE_TRACE() will pass in "void *data, > proto". > */ > -#define __DO_TRACE(tp, proto, args, cond, prercu, postrcu) \ > +#define __DO_TRACE(tp, proto, args, cond, rcucheck, prercu, postrcu) \ > do { \ > struct tracepoint_func *it_func_ptr; \ > void *it_func; \ > @@ -136,6 +136,8 @@ extern void syscall_unregfunc(void); > \ > if (!(cond)) \ > return; \ > + if (rcucheck) \ > + return; \ > prercu; \ > rcu_read_lock_sched_notrace(); \ > it_func_ptr = rcu_dereference_sched((tp)->funcs); \ > @@ -151,7 +153,7 @@ extern void syscall_unregfunc(void); > } while (0) > > #ifndef MODULE > -#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) > \ > +#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \ > static inline void trace_##name##_rcuidle(proto) \ > { \ > if (static_key_false(&__tracepoint_##name.key)) \ > @@ -159,6 +161,7 @@ extern void syscall_unregfunc(void); > TP_PROTO(data_proto), \ > TP_ARGS(data_args), \ > TP_CONDITION(cond), \ > + WARN_ON_ONCE(rcu_irq_enter_disabled()),\ > rcu_irq_enter_irqson(), \ > rcu_irq_exit_irqson()); \ > } > @@ -186,7 +189,7 @@ extern void syscall_unregfunc(void); > __DO_TRACE(&__tracepoint_##name, \ > TP_PROTO(data_proto), \ > TP_ARGS(data_args), \ > - TP_CONDITION(cond),,); \ > + TP_CONDITION(cond),0,,); \ > if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ > rcu_read_lock_sched_notrace(); \ > rcu_dereference_sched(__tracepoint_##name.funcs);\ > -- > 2.9.3 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
