5 files changed, 28 insertions, 19 deletions

diff --git a/Documentation/trace/histogram.txt b/Documentation/trace/histogram.txt
index e73bcf9cb5f3..7ffea6aa22e3 100644
--- a/Documentation/trace/histogram.txt
+++ b/Documentation/trace/histogram.txt
@@ -1729,35 +1729,35 @@ If a variable isn't a key variable or prefixed with 'vals=', the
 associated event field will be saved in a variable but won't be summed
 as a value:
 
-  # echo 'hist:keys=next_pid:ts1=common_timestamp ... >> event/trigger
+  # echo 'hist:keys=next_pid:ts1=common_timestamp ...' >> event/trigger
 
 Multiple variables can be assigned at the same time.  The below would
 result in both ts0 and b being created as variables, with both
 common_timestamp and field1 additionally being summed as values:
 
-  # echo 'hist:keys=pid:vals=$ts0,$b:ts0=common_timestamp,b=field1 ... >> \
+  # echo 'hist:keys=pid:vals=$ts0,$b:ts0=common_timestamp,b=field1 ...' >> \
         event/trigger
 
 Note that variable assignments can appear either preceding or
 following their use.  The command below behaves identically to the
 command above:
 
-  # echo 'hist:keys=pid:ts0=common_timestamp,b=field1:vals=$ts0,$b ... >> \
+  # echo 'hist:keys=pid:ts0=common_timestamp,b=field1:vals=$ts0,$b ...' >> \
         event/trigger
 
 Any number of variables not bound to a 'vals=' prefix can also be
 assigned by simply separating them with colons.  Below is the same
 thing but without the values being summed in the histogram:
 
-  # echo 'hist:keys=pid:ts0=common_timestamp:b=field1 ... >> event/trigger
+  # echo 'hist:keys=pid:ts0=common_timestamp:b=field1 ...' >> event/trigger
 
 Variables set as above can be referenced and used in expressions on
 another event.
 
 For example, here's how a latency can be calculated:
 
-  # echo 'hist:keys=pid,prio:ts0=common_timestamp ... >> event1/trigger
-  # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp-$ts0 ... >> event2/trigger
+  # echo 'hist:keys=pid,prio:ts0=common_timestamp ...' >> event1/trigger
+  # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp-$ts0 ...' >> event2/trigger
 
 In the first line above, the event's timetamp is saved into the
 variable ts0.  In the next line, ts0 is subtracted from the second
@@ -1766,7 +1766,7 @@ yet another variable, 'wakeup_lat'.  The hist trigger below in turn
 makes use of the wakeup_lat variable to compute a combined latency
 using the same key and variable from yet another event:
 
-  # echo 'hist:key=pid:wakeupswitch_lat=$wakeup_lat+$switchtime_lat ... >> event3/trigger
+  # echo 'hist:key=pid:wakeupswitch_lat=$wakeup_lat+$switchtime_lat ...' >> event3/trigger
 
 2.2.2 Synthetic Events
 ----------------------
@@ -1807,10 +1807,11 @@ the command that defined it with a '!':
 At this point, there isn't yet an actual 'wakeup_latency' event
 instantiated in the event subsytem - for this to happen, a 'hist
 trigger action' needs to be instantiated and bound to actual fields
-and variables defined on other events (see Section 6.3.3 below).
+and variables defined on other events (see Section 2.2.3 below on
+how that is done using hist trigger 'onmatch' action). Once that is
+done, the 'wakeup_latency' synthetic event instance is created.
 
-Once that is done, an event instance is created, and a histogram can
-be defined using it:
+A histogram can now be defined for the new synthetic event:
 
   # echo 'hist:keys=pid,prio,lat.log2:sort=pid,lat' >> \
         /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
@@ -1960,7 +1961,7 @@ hist trigger specification.
     back to that pid, the timestamp difference is calculated.  If the
     resulting latency, stored in wakeup_lat, exceeds the current
     maximum latency, the values specified in the save() fields are
-    recoreded:
+    recorded:
 
     # echo 'hist:keys=pid:ts0=common_timestamp.usecs \
             if comm=="cyclictest"' >> \
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;
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 34d9e9ce97c2..e7889f486ca1 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -239,6 +239,7 @@ cmd_record_mcount =						\
              "$(CC_FLAGS_FTRACE)" ]; then                       \
                 $(sub_cmd_record_mcount)                        \
         fi;
+endif # -record-mcount
 endif # CONFIG_FTRACE_MCOUNT_RECORD
 
 ifdef CONFIG_STACK_VALIDATION
@@ -263,7 +264,6 @@ ifneq ($(RETPOLINE_CFLAGS),)
   objtool_args += --retpoline
 endif
 endif
-endif
 
 
 ifdef CONFIG_MODVERSIONS