rv/monitor: Add the wwnr monitor
authorDaniel Bristot de Oliveira <bristot@kernel.org>
Fri, 29 Jul 2022 09:38:53 +0000 (11:38 +0200)
committerSteven Rostedt (Google) <rostedt@goodmis.org>
Sat, 30 Jul 2022 18:01:30 +0000 (14:01 -0400)
Per task wakeup while not running (wwnr) monitor.

This model is broken, the reason is that a task can be running in the
processor without being set as RUNNABLE. Think about a task about to
sleep:

1:      set_current_state(TASK_UNINTERRUPTIBLE);
2:      schedule();

And then imagine an IRQ happening in between the lines one and two,
waking the task up. BOOM, the wakeup will happen while the task is
running.

Q: Why do we need this model, so?
A: To test the reactors.

Link: https://lkml.kernel.org/r/473c0fc39967250fdebcff8b620311c11dccad30.1659052063.git.bristot@kernel.org
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Documentation/trace/rv/index.rst
Documentation/trace/rv/monitor_wwnr.rst [new file with mode: 0644]
include/trace/events/rv.h
kernel/trace/rv/Kconfig
kernel/trace/rv/Makefile
kernel/trace/rv/monitors/wwnr/wwnr.c [new file with mode: 0644]
kernel/trace/rv/monitors/wwnr/wwnr.h [new file with mode: 0644]
tools/verification/models/wwnr.dot [new file with mode: 0644]

index 4cb71ed..15fa966 100644 (file)
@@ -11,3 +11,4 @@ Runtime Verification
    da_monitor_synthesis.rst
    da_monitor_instrumentation.rst
    monitor_wip.rst
+   monitor_wwnr.rst
diff --git a/Documentation/trace/rv/monitor_wwnr.rst b/Documentation/trace/rv/monitor_wwnr.rst
new file mode 100644 (file)
index 0000000..80f1777
--- /dev/null
@@ -0,0 +1,45 @@
+Monitor wwnr
+============
+
+- Name: wwrn - wakeup while not running
+- Type: per-task deterministic automaton
+- Author: Daniel Bristot de Oliveira <bristot@kernel.org>
+
+Description
+-----------
+
+This is a per-task sample monitor, with the following
+definition::
+
+               |
+               |
+               v
+    wakeup   +-------------+
+  +--------- |             |
+  |          | not_running |
+  +--------> |             | <+
+             +-------------+  |
+               |              |
+               | switch_in    | switch_out
+               v              |
+             +-------------+  |
+             |   running   | -+
+             +-------------+
+
+This model is borken, the reason is that a task can be running
+in the processor without being set as RUNNABLE. Think about a
+task about to sleep::
+
+  1:      set_current_state(TASK_UNINTERRUPTIBLE);
+  2:      schedule();
+
+And then imagine an IRQ happening in between the lines one and two,
+waking the task up. BOOM, the wakeup will happen while the task is
+running.
+
+- Why do we need this model, so?
+- To test the reactors.
+
+Specification
+-------------
+Grapviz Dot file in tools/verification/models/wwnr.dot
index e972f27..56592da 100644 (file)
@@ -122,6 +122,18 @@ DECLARE_EVENT_CLASS(error_da_monitor_id,
                __entry->event,
                __entry->state)
 );
+
+#ifdef CONFIG_RV_MON_WWNR
+/* id is the pid of the task */
+DEFINE_EVENT(event_da_monitor_id, event_wwnr,
+            TP_PROTO(int id, char *state, char *event, char *next_state, bool final_state),
+            TP_ARGS(id, state, event, next_state, final_state));
+
+DEFINE_EVENT(error_da_monitor_id, error_wwnr,
+            TP_PROTO(int id, char *state, char *event),
+            TP_ARGS(id, state, event));
+#endif /* CONFIG_RV_MON_WWNR */
+
 #endif /* CONFIG_DA_MON_EVENTS_ID */
 #endif /* _TRACE_RV_H */
 
index e50f334..b259d6e 100644 (file)
@@ -38,6 +38,18 @@ config RV_MON_WIP
          For further information, see:
            Documentation/trace/rv/monitor_wip.rst
 
+config RV_MON_WWNR
+       depends on RV
+       select DA_MON_EVENTS_ID
+       bool "wwnr monitor"
+       help
+         Enable wwnr (wakeup while not running) sample monitor, this is a
+         sample monitor that illustrates the usage of per-task monitor.
+         The model is borken on purpose: it serves to test reactors.
+
+         For further information, see:
+           Documentation/trace/rv/monitor_wwnr.rst
+
 config RV_REACTORS
        bool "Runtime verification reactors"
        default y
index b41109d..af0ff9a 100644 (file)
@@ -3,3 +3,4 @@
 obj-$(CONFIG_RV) += rv.o
 obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
 obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
+obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.c b/kernel/trace/rv/monitors/wwnr/wwnr.c
new file mode 100644 (file)
index 0000000..599225d
--- /dev/null
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <rv/instrumentation.h>
+#include <rv/da_monitor.h>
+
+#define MODULE_NAME "wwnr"
+
+#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+
+#include "wwnr.h"
+
+struct rv_monitor rv_wwnr;
+DECLARE_DA_MON_PER_TASK(wwnr, unsigned char);
+
+static void handle_switch(void *data, bool preempt, struct task_struct *p,
+                         struct task_struct *n, unsigned int prev_state)
+{
+       /* start monitoring only after the first suspension */
+       if (prev_state == TASK_INTERRUPTIBLE)
+               da_handle_start_event_wwnr(p, switch_out_wwnr);
+       else
+               da_handle_event_wwnr(p, switch_out_wwnr);
+
+       da_handle_event_wwnr(n, switch_in_wwnr);
+}
+
+static void handle_wakeup(void *data, struct task_struct *p)
+{
+       da_handle_event_wwnr(p, wakeup_wwnr);
+}
+
+static int enable_wwnr(void)
+{
+       int retval;
+
+       retval = da_monitor_init_wwnr();
+       if (retval)
+               return retval;
+
+       rv_attach_trace_probe("wwnr", sched_switch, handle_switch);
+       rv_attach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+       return 0;
+}
+
+static void disable_wwnr(void)
+{
+       rv_wwnr.enabled = 0;
+
+       rv_detach_trace_probe("wwnr", sched_switch, handle_switch);
+       rv_detach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+       da_monitor_destroy_wwnr();
+}
+
+struct rv_monitor rv_wwnr = {
+       .name = "wwnr",
+       .description = "wakeup while not running per-task testing model.",
+       .enable = enable_wwnr,
+       .disable = disable_wwnr,
+       .reset = da_monitor_reset_all_wwnr,
+       .enabled = 0,
+};
+
+static int register_wwnr(void)
+{
+       rv_register_monitor(&rv_wwnr);
+       return 0;
+}
+
+static void unregister_wwnr(void)
+{
+       rv_unregister_monitor(&rv_wwnr);
+}
+
+module_init(register_wwnr);
+module_exit(unregister_wwnr);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <bristot@kernel.org>");
+MODULE_DESCRIPTION("wwnr: wakeup while not running monitor");
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.h b/kernel/trace/rv/monitors/wwnr/wwnr.h
new file mode 100644 (file)
index 0000000..d1afe55
--- /dev/null
@@ -0,0 +1,46 @@
+/*
+ * Automatically generated C representation of wwnr automaton
+ * For further information about this format, see kernel documentation:
+ *   Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_wwnr {
+       not_running_wwnr = 0,
+       running_wwnr,
+       state_max_wwnr
+};
+
+#define INVALID_STATE state_max_wwnr
+
+enum events_wwnr {
+       switch_in_wwnr = 0,
+       switch_out_wwnr,
+       wakeup_wwnr,
+       event_max_wwnr
+};
+
+struct automaton_wwnr {
+       char *state_names[state_max_wwnr];
+       char *event_names[event_max_wwnr];
+       unsigned char function[state_max_wwnr][event_max_wwnr];
+       unsigned char initial_state;
+       bool final_states[state_max_wwnr];
+};
+
+struct automaton_wwnr automaton_wwnr = {
+       .state_names = {
+               "not_running",
+               "running"
+       },
+       .event_names = {
+               "switch_in",
+               "switch_out",
+               "wakeup"
+       },
+       .function = {
+               {       running_wwnr,      INVALID_STATE,   not_running_wwnr },
+               {      INVALID_STATE,   not_running_wwnr,      INVALID_STATE },
+       },
+       .initial_state = not_running_wwnr,
+       .final_states = { 1, 0 },
+};
diff --git a/tools/verification/models/wwnr.dot b/tools/verification/models/wwnr.dot
new file mode 100644 (file)
index 0000000..1b206e8
--- /dev/null
@@ -0,0 +1,16 @@
+digraph state_automaton {
+       {node [shape = plaintext, style=invis, label=""] "__init_not_running"};
+       {node [shape = ellipse] "not_running"};
+       {node [shape = plaintext] "not_running"};
+       {node [shape = plaintext] "running"};
+       "__init_not_running" -> "not_running";
+       "not_running" [label = "not_running", color = green3];
+       "not_running" -> "not_running" [ label = "wakeup" ];
+       "not_running" -> "running" [ label = "switch_in" ];
+       "running" [label = "running"];
+       "running" -> "not_running" [ label = "switch_out" ];
+       { rank = min ;
+               "__init_not_running";
+               "not_running";
+       }
+}