Merge tag 'trace-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "This contains a few fixes and a clean up.

   - a bad merge caused an "endif" to go in the wrong place in
     scripts/Makefile.build

   - softirq tracing fix for tracing that corrupts lockdep and causes a
     false splat

   - histogram documentation typo fixes

   - fix a bad memory reference when passing in no filter to the filter
     code

   - simplify code by using the swap macro instead of open coding the
     swap"

* tag 'trace-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcount
  tracing: Fix some errors in histogram documentation
  tracing: Use swap macro in update_max_tr
  softirq: Reorder trace_softirqs_on to prevent lockdep splat
  tracing: Check for no filter when processing event filters

3 files changed, 15 insertions, 7 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index de2f57fddc04..900dcfee542c 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -139,9 +139,13 @@ static void __local_bh_enable(unsigned int cnt)
 {
 	lockdep_assert_irqs_disabled();
 
+	if (preempt_count() == cnt)
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
+
 	if (softirq_count() == (cnt & SOFTIRQ_MASK))
 		trace_softirqs_on(_RET_IP_);
-	preempt_count_sub(cnt);
+
+	__preempt_count_sub(cnt);
 }
 
 /*
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c9336e98ac59..a0079b4c7a49 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1360,8 +1360,6 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 void
 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
-	struct ring_buffer *buf;
-
 	if (tr->stop_count)
 		return;
 
@@ -1375,9 +1373,7 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 
 	arch_spin_lock(&tr->max_lock);
 
-	buf = tr->trace_buffer.buffer;
-	tr->trace_buffer.buffer = tr->max_buffer.buffer;
-	tr->max_buffer.buffer = buf;
+	swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
 
 	__update_max_tr(tr, tsk, cpu);
 	arch_spin_unlock(&tr->max_lock);
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index e1c818dbc0d7..0dceb77d1d42 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -78,7 +78,8 @@ static const char * ops[] = { OPS };
 	C(TOO_MANY_PREDS,	"Too many terms in predicate expression"), \
 	C(INVALID_FILTER,	"Meaningless filter expression"),	\
 	C(IP_FIELD_ONLY,	"Only 'ip' field is supported for function trace"), \
-	C(INVALID_VALUE,	"Invalid value (did you forget quotes)?"),
+	C(INVALID_VALUE,	"Invalid value (did you forget quotes)?"), \
+	C(NO_FILTER,		"No filter found"),
 
 #undef C
 #define C(a, b)		FILT_ERR_##a
@@ -550,6 +551,13 @@ predicate_parse(const char *str, int nr_parens, int nr_preds,
 		goto out_free;
 	}
 
+	if (!N) {
+		/* No program? */
+		ret = -EINVAL;
+		parse_error(pe, FILT_ERR_NO_FILTER, ptr - str);
+		goto out_free;
+	}
+
 	prog[N].pred = NULL;					/* #13 */
 	prog[N].target = 1;		/* TRUE */
 	prog[N+1].pred = NULL;