Merge tag 'trace-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Functional fixes:

   - Fix big endian conversion for arm64 in recordmcount processing

   - Fix timestamp corruption in ring buffer on discarding events

   - Fix memory leak in __create_synth_event()

   - Skip selftests if tracing is disabled as it will cause them to
     fail.

  Non-functional fixes:

   - Fix help text in Kconfig

   - Remove duplicate prototype for trace_empty()

   - Fix stale comment about the trace_event_call flags.

  Self test update:

   - Add more information to the validation output of when a corrupt
     timestamp is found in the ring buffer, and also trigger a warning
     to make sure that tests catch it"

* tag 'trace-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix comment about the trace_event_call flags
  tracing: Skip selftests if tracing is disabled
  tracing: Fix memory leak in __create_synth_event()
  ring-buffer: Add a little more information and a WARN when time stamp going backwards is detected
  ring-buffer: Force before_stamp and write_stamp to be different on discard
  tracing: Fix help text of TRACEPOINT_BENCHMARK in Kconfig
  tracing: Remove duplicate declaration from trace.h
  ftrace: Have recordmcount use w8 to read relp->r_info in arm64_is_fake_mcount

Author: torvalds

include/linux/trace_events.h

@@ -349,15 +349,8 @@ struct trace_event_call {
 	struct event_filter	*filter;
 	void			*mod;
 	void			*data;
-	/*
-	 *   bit 0:		filter_active
-	 *   bit 1:		allow trace by non root (cap any)
-	 *   bit 2:		failed to apply filter
-	 *   bit 3:		trace internal event (do not enable)
-	 *   bit 4:		Event was enabled by module
-	 *   bit 5:		use call filter rather than file filter
-	 *   bit 6:		Event is a tracepoint
-	 */
+
+	/* See the TRACE_EVENT_FL_* flags above */
 	int			flags; /* static flags of different events */
 
 #ifdef CONFIG_PERF_EVENTS

kernel/trace/Kconfig

@@ -694,7 +694,7 @@ config TRACEPOINT_BENCHMARK
 	help
 	 This option creates the tracepoint "benchmark:benchmark_event".
 	 When the tracepoint is enabled, it kicks off a kernel thread that
-	 goes into an infinite loop (calling cond_sched() to let other tasks
+	 goes into an infinite loop (calling cond_resched() to let other tasks
 	 run), and calls the tracepoint. Each iteration will record the time
 	 it took to write to the tracepoint and the next iteration that
 	 data will be passed to the tracepoint itself. That is, the tracepoint

kernel/trace/ring_buffer.c

@@ -2814,6 +2814,17 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
 				       write_stamp, write_stamp - delta))
 			return 0;
 
+		/*
+		 * It's possible that the event time delta is zero
+		 * (has the same time stamp as the previous event)
+		 * in which case write_stamp and before_stamp could
+		 * be the same. In such a case, force before_stamp
+		 * to be different than write_stamp. It doesn't
+		 * matter what it is, as long as its different.
+		 */
+		if (!delta)
+			rb_time_set(&cpu_buffer->before_stamp, 0);
+
 		/*
 		 * If an event were to come in now, it would see that the
 		 * write_stamp and the before_stamp are different, and assume
@@ -3307,9 +3318,13 @@ static void check_buffer(struct ring_buffer_per_cpu *cpu_buffer,
 			goto out;
 		}
 		atomic_inc(&cpu_buffer->record_disabled);
-		pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld after:%lld\n",
-		       cpu_buffer->cpu,
-		       ts + info->delta, info->ts, info->delta, info->after);
+		/* There's some cases in boot up that this can happen */
+		WARN_ON_ONCE(system_state != SYSTEM_BOOTING);
+		pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld before:%lld after:%lld%s\n",
+			cpu_buffer->cpu,
+			ts + info->delta, info->ts, info->delta,
+			info->before, info->after,
+			full ? " (full)" : "");
 		dump_buffer_page(bpage, info, tail);
 		atomic_dec(&ts_dump);
 		/* Do not re-enable checking */

kernel/trace/trace.c

@@ -1929,6 +1929,12 @@ static int run_tracer_selftest(struct tracer *type)
 	if (!selftests_can_run)
 		return save_selftest(type);
 
+	if (!tracing_is_on()) {
+		pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
+			type->name);
+		return 0;
+	}
+
 	/*
 	 * Run a selftest on this tracer.
 	 * Here we reset the trace buffer, and set the current

kernel/trace/trace.h

@@ -605,7 +605,6 @@ void trace_graph_function(struct trace_array *tr,
 void trace_latency_header(struct seq_file *m);
 void trace_default_header(struct seq_file *m);
 void print_trace_header(struct seq_file *m, struct trace_iterator *iter);
-int trace_empty(struct trace_iterator *iter);
 
 void trace_graph_return(struct ftrace_graph_ret *trace);
 int trace_graph_entry(struct ftrace_graph_ent *trace);

kernel/trace/trace_events_synth.c

@@ -1225,8 +1225,10 @@ static int __create_synth_event(const char *name, const char *raw_fields)
 			goto err;
 		}
 
-		if (!argc)
+		if (!argc) {
+			argv_free(argv);
 			continue;
+		}
 
 		n_fields_this_loop = 0;
 		consumed = 0;

scripts/recordmcount.c

@@ -438,7 +438,7 @@ static int arm_is_fake_mcount(Elf32_Rel const *rp)
 
 static int arm64_is_fake_mcount(Elf64_Rel const *rp)
 {
-	return ELF64_R_TYPE(w(rp->r_info)) != R_AARCH64_CALL26;
+	return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26;
 }
 
 /* 64-bit EM_MIPS has weird ELF64_Rela.r_info.