Commit ccc319dc authored by Daniel Bristot de Oliveira's avatar Daniel Bristot de Oliveira Committed by Steven Rostedt (Google)

rv/monitor: Add the wwnr monitor

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: default avatarDaniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 10bde81c
......@@ -11,3 +11,4 @@ Runtime Verification
da_monitor_synthesis.rst
da_monitor_instrumentation.rst
monitor_wip.rst
monitor_wwnr.rst
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
......@@ -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 */
......
......@@ -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
......
......@@ -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
// 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");
/*
* 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 },
};
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";
}
}
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