[RFC V2 00/21] The Runtime Verification (RV) interface

From: Daniel Bristot de Oliveira
Date: Mon Feb 14 2022 - 06:28:58 EST

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Over the last years, I've been exploring the possibility of
verifying the Linux kernel behavior using Runtime Verification.

Runtime Verification (RV) is a lightweight (yet rigorous) method that
complements classical exhaustive verification techniques (such as model
checking and theorem proving) with a more practical approach for complex
systems.

Instead of relying on a fine-grained model of a system (e.g., a
re-implementation a instruction level), RV works by analyzing the trace of the
system's actual execution, comparing it against a formal specification of
the system behavior.

The usage of deterministic automaton for RV is a well-established
approach. In the specific case of the Linux kernel, you can check how
to model complex behavior of the Linux kernel with this paper:

DE OLIVEIRA, Daniel Bristot; CUCINOTTA, Tommaso; DE OLIVEIRA, Romulo Silva.
*Efficient formal verification for the Linux kernel.* In: International
Conference on Software Engineering and Formal Methods. Springer, Cham, 2019.
p. 315-332.

And how efficient is this approach here:

DE OLIVEIRA, Daniel B.; DE OLIVEIRA, Romulo S.; CUCINOTTA, Tommaso. *A thread
synchronization model for the PREEMPT_RT Linux kernel.* Journal of Systems
Architecture, 2020, 107: 101729.

tlrd: it is possible to model complex behaviors in a modular way, with
an acceptable overhead (even for production systems). See this
presentation at 2019's ELCE: https://www.youtube.com/watch?v=BfTuEHafNgg

Here I am proposing a more practical approach for the usage of deterministic
automata for runtime verification, and it includes:

- An interface for controlling the verification;
- A tool and set of headers that enables the automatic code
generation of the RV monitor (Monitor Synthesis);
- Sample monitors to evaluate the interface;
- A sample monitor developed in the context of the Elisa Project
demonstrating how to use RV in the context of safety-critical
systems.

Given that RV is a tracing consumer, the code is being placed inside the
tracing subsystem (Steven and I have been talking about it for a while).

The changes since V1 includes:
- rebased to the latest kernel;
- code cleanup;
- the watchdog dev monitor;
- safety app;

The TODO list still includes:
- Make per-task monitor use the task struct to store the
per monitor state (Suggested by peterz)
- Add a reactor tha enables the visualization of the visited
states via KCOV (Marco Elver & Dmitry Vyukov)
- Add a CRC method to check from user-space if the values
exported by the monitor were not corrupted by any other
kernel task (Gabriele Paoloni)

I am sending the V2 with some TODOs because I need
some feedback on the interface/files placement inside the kernel,
so I can adjust all the patches accordingly. Also, to make it possible
for people in the Elisa Project to evaluate the safety_app approach.

Daniel Bristot de Oliveira (21):
rv: Add Runtime Verification (RV) interface
rv: Add runtime reactors interface
rv/include: Add helper functions for deterministic automata
rv/include: Add deterministic automata monitor definition via C macros
rv/include: Add tracing helper functions
tools/rv: Add dot2c
tools/rv: Add dot2k
rv/monitor: Add the wip monitor skeleton created by dot2k
rv/monitor: wip instrumentation and Makefile/Kconfig entries
rv/monitor: Add the wwnr monitor skeleton created by dot2k
rv/monitor: wwnr instrumentation and Makefile/Kconfig entries
rv/reactor: Add the printk reactor
rv/reactor: Add the panic reactor
Documentation/rv: Add a basic documentation
Documentation/rv: Add deterministic automata monitor synthesis
documentation
Documentation/rv: Add deterministic automata instrumentation
documentation
watchdog/dev: Add tracepoints
rv/monitor: Add safe watchdog monitor
rv/monitor: Add safe watchdog nowayout monitor
rv/safety_app: Add an safety_app sample
Documentation/rv: Add watchdog-monitor documentation

Documentation/trace/index.rst | 1 +
.../trace/rv/da_monitor_instrumentation.rst | 230 ++++++
.../trace/rv/da_monitor_synthesis.rst | 286 +++++++
Documentation/trace/rv/index.rst | 9 +
.../trace/rv/runtime-verification.rst | 233 ++++++
Documentation/trace/rv/watchdog-monitor.rst | 307 ++++++++
drivers/watchdog/watchdog_dev.c | 41 +-
include/linux/rv.h | 31 +
include/linux/watchdog.h | 7 +-
include/rv/automata.h | 52 ++
include/rv/da_monitor.h | 398 ++++++++++
include/rv/trace_helpers.h | 69 ++
include/trace/events/watchdog.h | 103 +++
kernel/trace/Kconfig | 2 +
kernel/trace/Makefile | 2 +
kernel/trace/rv/Kconfig | 78 ++
kernel/trace/rv/Makefile | 10 +
kernel/trace/rv/monitor_safe_wtd/model.h | 84 +++
kernel/trace/rv/monitor_safe_wtd/safe_wtd.c | 322 ++++++++
kernel/trace/rv/monitor_safe_wtd/safe_wtd.h | 64 ++
kernel/trace/rv/monitor_safe_wtd_nwo/model.h | 61 ++
.../rv/monitor_safe_wtd_nwo/safe_wtd_nwo.c | 309 ++++++++
.../rv/monitor_safe_wtd_nwo/safe_wtd_nwo.h | 64 ++
kernel/trace/rv/monitor_wip/model.h | 38 +
kernel/trace/rv/monitor_wip/wip.c | 124 +++
kernel/trace/rv/monitor_wip/wip.h | 64 ++
kernel/trace/rv/monitor_wwnr/model.h | 38 +
kernel/trace/rv/monitor_wwnr/wwnr.c | 122 +++
kernel/trace/rv/monitor_wwnr/wwnr.h | 70 ++
kernel/trace/rv/reactor_panic.c | 44 ++
kernel/trace/rv/reactor_printk.c | 43 ++
kernel/trace/rv/rv.c | 700 +++++++++++++++++
kernel/trace/rv/rv.h | 50 ++
kernel/trace/rv/rv_reactors.c | 478 ++++++++++++
kernel/trace/trace.c | 4 +
kernel/trace/trace.h | 2 +
tools/tracing/rv/dot2/Makefile | 26 +
tools/tracing/rv/dot2/automata.py | 179 +++++
tools/tracing/rv/dot2/dot2c | 30 +
tools/tracing/rv/dot2/dot2c.py | 240 ++++++
tools/tracing/rv/dot2/dot2k | 46 ++
tools/tracing/rv/dot2/dot2k.py | 184 +++++
.../rv/dot2/dot2k_templates/main_global.c | 96 +++
.../rv/dot2/dot2k_templates/main_global.h | 64 ++
.../rv/dot2/dot2k_templates/main_per_cpu.c | 96 +++
.../rv/dot2/dot2k_templates/main_per_cpu.h | 64 ++
.../rv/dot2/dot2k_templates/main_per_task.c | 96 +++
.../rv/dot2/dot2k_templates/main_per_task.h | 70 ++
tools/tracing/rv/safety_app/Makefile | 51 ++
tools/tracing/rv/safety_app/safety_app.c | 713 ++++++++++++++++++
50 files changed, 6486 insertions(+), 9 deletions(-)
create mode 100644 Documentation/trace/rv/da_monitor_instrumentation.rst
create mode 100644 Documentation/trace/rv/da_monitor_synthesis.rst
create mode 100644 Documentation/trace/rv/index.rst
create mode 100644 Documentation/trace/rv/runtime-verification.rst
create mode 100644 Documentation/trace/rv/watchdog-monitor.rst
create mode 100644 include/linux/rv.h
create mode 100644 include/rv/automata.h
create mode 100644 include/rv/da_monitor.h
create mode 100644 include/rv/trace_helpers.h
create mode 100644 include/trace/events/watchdog.h
create mode 100644 kernel/trace/rv/Kconfig
create mode 100644 kernel/trace/rv/Makefile
create mode 100644 kernel/trace/rv/monitor_safe_wtd/model.h
create mode 100644 kernel/trace/rv/monitor_safe_wtd/safe_wtd.c
create mode 100644 kernel/trace/rv/monitor_safe_wtd/safe_wtd.h
create mode 100644 kernel/trace/rv/monitor_safe_wtd_nwo/model.h
create mode 100644 kernel/trace/rv/monitor_safe_wtd_nwo/safe_wtd_nwo.c
create mode 100644 kernel/trace/rv/monitor_safe_wtd_nwo/safe_wtd_nwo.h
create mode 100644 kernel/trace/rv/monitor_wip/model.h
create mode 100644 kernel/trace/rv/monitor_wip/wip.c
create mode 100644 kernel/trace/rv/monitor_wip/wip.h
create mode 100644 kernel/trace/rv/monitor_wwnr/model.h
create mode 100644 kernel/trace/rv/monitor_wwnr/wwnr.c
create mode 100644 kernel/trace/rv/monitor_wwnr/wwnr.h
create mode 100644 kernel/trace/rv/reactor_panic.c
create mode 100644 kernel/trace/rv/reactor_printk.c
create mode 100644 kernel/trace/rv/rv.c
create mode 100644 kernel/trace/rv/rv.h
create mode 100644 kernel/trace/rv/rv_reactors.c
create mode 100644 tools/tracing/rv/dot2/Makefile
create mode 100644 tools/tracing/rv/dot2/automata.py
create mode 100644 tools/tracing/rv/dot2/dot2c
create mode 100644 tools/tracing/rv/dot2/dot2c.py
create mode 100644 tools/tracing/rv/dot2/dot2k
create mode 100644 tools/tracing/rv/dot2/dot2k.py
create mode 100644 tools/tracing/rv/dot2/dot2k_templates/main_global.c
create mode 100644 tools/tracing/rv/dot2/dot2k_templates/main_global.h
create mode 100644 tools/tracing/rv/dot2/dot2k_templates/main_per_cpu.c
create mode 100644 tools/tracing/rv/dot2/dot2k_templates/main_per_cpu.h
create mode 100644 tools/tracing/rv/dot2/dot2k_templates/main_per_task.c
create mode 100644 tools/tracing/rv/dot2/dot2k_templates/main_per_task.h
create mode 100644 tools/tracing/rv/safety_app/Makefile
create mode 100644 tools/tracing/rv/safety_app/safety_app.c

--
2.33.1

Next message: Andreas Schwab: "Re: [PATCH] riscv/efi_stub: Fix get_boot_hartid_from_fdt() return value"
Previous message: Sebastian Andrzej Siewior: "Re: [PATCH] random: set fast pool count to zero in cpuhp teardown"
Next in thread: Daniel Bristot de Oliveira: "[RFC V2 03/21] rv/include: Add helper functions for deterministic automata"
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