Files
turso/simulator/main.rs
Pekka Enberg 9a1bd2112d Merge 'Run simulator under Miri' from Bob Peterson
This adds support for running the simulator under Miri to detect UB.
There are a few things to note about Miri and its limitations
- It has limited `libc` coverage, so it's not really possible to have
Miri help with `UringIO`/`UringFile` or `UnixIO`/`UnixFile`. That's a
big gap ☹️
- It **can** work for `GenericIO`/`GenericFile`, which only uses `std`
- It can't call external C libraries, so even using `sqlite` is out
(hence adding `--disable-integrity-check` to the simulator for Miri use)
- It runs on nightly, consequently there are a few new lints that don't
exist on turso's pinned version of rustc
Some questions I have about this MR
- I made `GenericFile::{lock_file,unlock_file}` noops so I could use
`GenericIO`. This isn't great, but if/when you update from Rust 1.88.0
to 1.89.0, `std::File::{lock,lock_shared,unlock}` will be stabilized and
available. Should I note that as a TODO or something?
- Previously, the sim runner shelled out to `git` to get stuff like the
current git hash and the repo directory. For Miri, that's out, and so is
`git2`. Unfortunately, `gix` is also out since it has a required
dependency that uses inline assembly, which Miri doesn't like. I wrote a
hacky shim that uses only std to look for `.git` and find the hash that
HEAD is pointing to. It doesn't deal with stuff like packed-refs or the
repo being a secondary one made with `git worktree`. I'm happy to
support that, but wanted to hear from maintainers before doing more
work.
Two UB occurrences I already found:
- `TursoRwLock::read` used `AtomicU64::compare_exchange_weak`, which is
(evidently) [allowed to spuriously fail](https://doc.rust-lang.org/std/s
ync/atomic/struct.AtomicU64.html#method.compare_exchange_weak) in
exchange for perf. Miri forces this behavior, which triggers trivial
read deadlocks even with zero readers/writers. I changed it to
`compare_exchange`, but I'm not an atomics expert.
- Uninitialized read in non-Unix
`core::storage::buffer_pool::arena::alloc`. This is a simple one,
resolved by using `std::alloc::alloc_zeroed` instead of
`std::alloc::alloc`
Moving forward, I'd be interested in potentially getting the tests to
run in Miri, too. `tokio` looks like a good example of a project with
partial coverage that runs it where they can. They have some extra test
config to allow as many as possible to run under Miri, with
appropriately scaled-down parameter values since Miri is super slow

Closes #3720
2025-10-14 09:26:55 +03:00

712 lines
25 KiB
Rust

#![allow(clippy::arc_with_non_send_sync)]
use anyhow::anyhow;
use clap::Parser;
use generation::plan::{InteractionPlan, InteractionPlanState};
use notify::event::{DataChange, ModifyKind};
use notify::{EventKind, RecursiveMode, Watcher};
use rand::prelude::*;
use runner::bugbase::{Bug, BugBase, LoadedBug};
use runner::cli::{SimulatorCLI, SimulatorCommand};
use runner::differential;
use runner::env::SimulatorEnv;
use runner::execution::{Execution, ExecutionHistory, ExecutionResult, execute_interactions};
use std::any::Any;
use std::backtrace::Backtrace;
use std::fs::OpenOptions;
use std::io::{IsTerminal, Write};
use std::path::Path;
use std::rc::Rc;
use std::sync::{Arc, Mutex, mpsc};
use tracing_subscriber::EnvFilter;
use tracing_subscriber::field::MakeExt;
use tracing_subscriber::fmt::format;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
use crate::generation::plan::{ConnectionState, InteractionPlanIterator};
use crate::profiles::Profile;
use crate::runner::doublecheck;
use crate::runner::env::{Paths, SimulationPhase, SimulationType};
mod common;
mod generation;
mod model;
mod profiles;
mod runner;
mod shrink;
fn main() -> anyhow::Result<()> {
init_logger()?;
let mut cli_opts = SimulatorCLI::parse();
cli_opts.validate()?;
let profile = Profile::parse_from_type(cli_opts.profile.clone())?;
tracing::debug!(sim_profile = ?profile);
if let Some(ref command) = cli_opts.subcommand {
match command {
SimulatorCommand::List => {
let mut bugbase = BugBase::load()?;
bugbase.list_bugs()
}
SimulatorCommand::Loop { n, short_circuit } => {
banner();
for i in 0..*n {
println!("iteration {i}");
let result = testing_main(&cli_opts, &profile);
if result.is_err() && *short_circuit {
println!("short circuiting after {i} iterations");
return result;
} else if result.is_err() {
println!("iteration {i} failed");
} else {
println!("iteration {i} succeeded");
}
}
Ok(())
}
SimulatorCommand::Test { filter } => {
let mut bugbase = BugBase::load()?;
let bugs = bugbase.load_bugs()?;
let mut bugs = bugs
.into_iter()
.flat_map(|bug| {
let runs = bug
.runs
.into_iter()
.filter_map(|run| run.error.clone().map(|_| run))
.filter(|run| run.error.as_ref().unwrap().contains(filter))
.map(|run| run.cli_options)
.collect::<Vec<_>>();
runs.into_iter()
.map(|mut cli_opts| {
cli_opts.seed = Some(bug.seed);
cli_opts.load = None;
cli_opts
})
.collect::<Vec<_>>()
})
.collect::<Vec<_>>();
bugs.sort();
bugs.dedup_by(|a, b| a == b);
println!(
"found {} previously triggered configurations with {}",
bugs.len(),
filter
);
let results = bugs
.into_iter()
.map(|cli_opts| testing_main(&cli_opts, &profile))
.collect::<Vec<_>>();
let (successes, failures): (Vec<_>, Vec<_>) =
results.into_iter().partition(|result| result.is_ok());
println!("the results of the change are:");
println!("\t{} successful runs", successes.len());
println!("\t{} failed runs", failures.len());
Ok(())
}
SimulatorCommand::PrintSchema => {
let schema = schemars::schema_for!(crate::Profile);
println!("{}", serde_json::to_string_pretty(&schema).unwrap());
Ok(())
}
}
} else {
banner();
testing_main(&cli_opts, &profile)
}
}
fn testing_main(cli_opts: &SimulatorCLI, profile: &Profile) -> anyhow::Result<()> {
let mut bugbase = if cli_opts.disable_bugbase {
None
} else {
tracing::trace!("loading bugbase");
Some(BugBase::load()?)
};
let (seed, mut env, plans) = setup_simulation(bugbase.as_mut(), cli_opts, profile);
if cli_opts.watch {
watch_mode(env).unwrap();
return Ok(());
}
let paths = env.paths.clone();
if cli_opts.differential {
env.type_ = SimulationType::Differential;
} else if cli_opts.doublecheck {
env.type_ = SimulationType::Doublecheck;
}
let result = run_simulator(bugbase.as_mut(), cli_opts, env, plans);
// Print the seed, the locations of the database and the plan file at the end again for easily accessing them.
println!("seed: {seed}");
println!("path: {}", paths.base.display());
if !cli_opts.keep_files && result.is_ok() {
paths.delete_all_files();
}
result
}
fn watch_mode(env: SimulatorEnv) -> notify::Result<()> {
let (tx, rx) = mpsc::channel::<notify::Result<notify::Event>>();
println!("watching {:?}", env.get_plan_path());
// Use recommended_watcher() to automatically select the best implementation
// for your platform. The `EventHandler` passed to this constructor can be a
// closure, a `std::sync::mpsc::Sender`, a `crossbeam_channel::Sender`, or
// another type the trait is implemented for.
let mut watcher = notify::recommended_watcher(tx)?;
// Add a path to be watched. All files and directories at that path and
// below will be monitored for changes.
watcher.watch(&env.get_plan_path(), RecursiveMode::NonRecursive)?;
// Block forever, printing out events as they come in
let last_execution = Arc::new(Mutex::new(Execution::new(0, 0)));
for res in rx {
match res {
Ok(event) => {
if let EventKind::Modify(ModifyKind::Data(DataChange::Content)) = event.kind {
tracing::info!("plan file modified, rerunning simulation");
let env = env.clone_without_connections();
let last_execution_ = last_execution.clone();
let result = SandboxedResult::from(
std::panic::catch_unwind(move || {
let mut env = env;
let plan_path = env.get_plan_path();
let plan = InteractionPlan::compute_via_diff(&plan_path);
env.clear();
let env = Arc::new(Mutex::new(env.clone_without_connections()));
run_simulation_default(env, plan, last_execution_.clone())
}),
last_execution.clone(),
);
match result {
SandboxedResult::Correct => {
tracing::info!("simulation succeeded");
println!("simulation succeeded");
}
SandboxedResult::Panicked { error, .. }
| SandboxedResult::FoundBug { error, .. } => {
tracing::error!("simulation failed: '{}'", error);
}
}
}
}
Err(e) => println!("watch error: {e:?}"),
}
}
Ok(())
}
fn run_simulator(
mut bugbase: Option<&mut BugBase>,
cli_opts: &SimulatorCLI,
env: SimulatorEnv,
plan: InteractionPlan,
) -> anyhow::Result<()> {
std::panic::set_hook(Box::new(move |info| {
tracing::error!("panic occurred");
let payload = info.payload();
if let Some(s) = payload.downcast_ref::<&str>() {
tracing::error!("{}", s);
} else if let Some(s) = payload.downcast_ref::<String>() {
tracing::error!("{}", s);
} else {
tracing::error!("unknown panic payload");
}
let bt = Backtrace::force_capture();
tracing::error!("captured backtrace:\n{}", bt);
}));
let last_execution = Arc::new(Mutex::new(Execution::new(0, 0)));
let mut gen_rng = env.gen_rng();
let env = Arc::new(Mutex::new(env));
// Need to wrap in Rc Mutex due to the UnwindSafe barrier
let plan = Rc::new(Mutex::new(plan));
let result = {
let sim_execution = last_execution.clone();
let sim_plan = plan.clone();
let sim_env = env.clone();
SandboxedResult::from(
std::panic::catch_unwind(move || {
let mut sim_plan = sim_plan.lock().unwrap();
let plan = sim_plan.generator(&mut gen_rng);
run_simulation(sim_env, plan, sim_execution)
}),
last_execution.clone(),
)
};
env.clear_poison();
plan.clear_poison();
let env = env.lock().unwrap();
let plan = plan.lock().unwrap();
tracing::info!("{}", plan.stats());
std::fs::write(env.get_plan_path(), plan.to_string()).unwrap();
std::fs::write(
env.get_plan_path().with_extension("json"),
serde_json::to_string_pretty(&*plan).unwrap(),
)
.unwrap();
// No doublecheck, run shrinking if panicking or found a bug.
match &result {
SandboxedResult::Correct => {
tracing::info!("simulation succeeded");
println!("simulation succeeded");
Ok(())
}
SandboxedResult::Panicked {
error,
last_execution,
}
| SandboxedResult::FoundBug {
error,
last_execution,
..
} => {
if let SandboxedResult::FoundBug { history, .. } = &result {
// No panic occurred, so write the history to a file
let f = std::fs::File::create(&env.paths.history).unwrap();
let mut f = std::io::BufWriter::new(f);
for execution in history.history.iter() {
writeln!(
f,
"{} {}",
execution.connection_index, execution.interaction_index,
)
.unwrap();
}
}
tracing::error!("simulation failed: '{}'", error);
if cli_opts.disable_heuristic_shrinking && !cli_opts.enable_brute_force_shrinking {
tracing::info!("shrinking is disabled, skipping shrinking");
if let Some(bugbase) = bugbase.as_deref_mut() {
bugbase
.add_bug(env.opts.seed, plan.clone(), Some(error.clone()), cli_opts)
.unwrap();
}
return Err(anyhow!("failed with error: '{}'", error));
}
tracing::info!("Starting to shrink");
let (shrunk_plan, shrunk) = if !cli_opts.disable_heuristic_shrinking {
let shrunk_plan = plan.shrink_interaction_plan(last_execution);
tracing::info!("{}", shrunk_plan.stats());
// Write the shrunk plan to a file
let shrunk_plan_path = env
.paths
.plan(&SimulationType::Default, &SimulationPhase::Shrink);
let mut f = std::fs::File::create(&shrunk_plan_path).unwrap();
tracing::trace!("writing shrunk plan to {}", shrunk_plan_path.display());
f.write_all(shrunk_plan.to_string().as_bytes()).unwrap();
let last_execution = Arc::new(Mutex::new(*last_execution));
let env = env.clone_at_phase(SimulationPhase::Shrink);
let env = Arc::new(Mutex::new(env));
let shrunk = SandboxedResult::from(
std::panic::catch_unwind(|| {
let plan = shrunk_plan.static_iterator();
run_simulation(env.clone(), plan, last_execution.clone())
}),
last_execution,
);
(shrunk_plan, shrunk)
} else {
(plan.clone(), result.clone())
};
match (&shrunk, &result) {
(
SandboxedResult::Panicked { error: e1, .. },
SandboxedResult::Panicked { error: e2, .. },
)
| (
SandboxedResult::FoundBug { error: e1, .. },
SandboxedResult::FoundBug { error: e2, .. },
) => {
if let Some(bugbase) = bugbase.as_deref_mut() {
tracing::trace!(
"adding bug to bugbase, seed: {}, plan: {}, error: {}",
env.opts.seed,
plan.len(),
error
);
bugbase
.add_bug(env.opts.seed, plan.clone(), Some(error.clone()), cli_opts)
.unwrap();
}
if e1 != e2 {
tracing::error!(
?shrunk,
?result,
"shrinking failed, the error was not properly reproduced"
);
Err(anyhow!("failed with error: '{}'", error))
} else {
let seed = env.opts.seed;
let env = env.clone_at_phase(SimulationPhase::Shrink);
let env = Arc::new(Mutex::new(env));
let final_plan = if cli_opts.enable_brute_force_shrinking {
let brute_shrunk_plan =
shrunk_plan.brute_shrink_interaction_plan(&shrunk, env.clone());
tracing::info!("Brute force shrinking completed");
brute_shrunk_plan
} else {
shrunk_plan
};
tracing::info!(
"shrinking succeeded, reduced the plan from {} to {}",
plan.len(),
final_plan.len()
);
// Save the shrunk database
if let Some(bugbase) = bugbase.as_deref_mut() {
bugbase.make_shrunk(
seed,
cli_opts,
final_plan.clone(),
Some(e1.clone()),
)?;
}
Err(anyhow!("failed with error: '{}'", e1))
}
}
(_, SandboxedResult::Correct) => {
unreachable!("shrinking should never be called on a correct simulation")
}
_ => {
tracing::error!(
?shrunk,
?result,
"shrinking failed, the error was not properly reproduced"
);
if let Some(bugbase) = bugbase {
bugbase
.add_bug(env.opts.seed, plan.clone(), Some(error.clone()), cli_opts)
.unwrap();
}
Err(anyhow!("failed with error: '{}'", error))
}
}
}
}
}
#[derive(Debug, Clone)]
enum SandboxedResult {
Panicked {
error: String,
last_execution: Execution,
},
#[expect(dead_code)]
FoundBug {
error: String,
history: ExecutionHistory,
last_execution: Execution,
},
Correct,
}
impl SandboxedResult {
fn from(
result: Result<ExecutionResult, Box<dyn Any + Send>>,
last_execution: Arc<Mutex<Execution>>,
) -> Self {
match result {
Ok(ExecutionResult { error: None, .. }) => SandboxedResult::Correct,
Ok(ExecutionResult { error: Some(e), .. }) => {
let error = format!("{e:?}");
let last_execution = last_execution.lock().unwrap();
SandboxedResult::Panicked {
error,
last_execution: *last_execution,
}
}
Err(payload) => {
tracing::error!("panic occurred");
let err = if let Some(s) = payload.downcast_ref::<&str>() {
tracing::error!("{}", s);
s.to_string()
} else if let Some(s) = payload.downcast_ref::<String>() {
tracing::error!("{}", s);
s.to_string()
} else {
tracing::error!("unknown panic payload");
"unknown panic payload".to_string()
};
last_execution.clear_poison();
SandboxedResult::Panicked {
error: err,
last_execution: *last_execution.lock().unwrap(),
}
}
}
}
}
fn setup_simulation(
bugbase: Option<&mut BugBase>,
cli_opts: &SimulatorCLI,
profile: &Profile,
) -> (u64, SimulatorEnv, InteractionPlan) {
if let Some(seed) = &cli_opts.load {
let seed = seed.parse::<u64>().expect("seed should be a number");
let bugbase = bugbase.expect("BugBase must be enabled to load a bug");
tracing::info!("seed={}", seed);
let bug = bugbase
.get_bug(seed)
.unwrap_or_else(|| panic!("bug '{seed}' not found in bug base"));
let paths = bugbase.paths(seed);
if !paths.base.exists() {
std::fs::create_dir_all(&paths.base).unwrap();
}
let env = SimulatorEnv::new(
bug.seed(),
cli_opts,
paths,
SimulationType::Default,
profile,
);
let plan = match bug {
Bug::Loaded(LoadedBug { plan, .. }) => plan.clone(),
Bug::Unloaded { seed } => {
let seed = *seed;
bugbase
.load_bug(seed)
.unwrap_or_else(|_| panic!("could not load bug '{seed}' in bug base"))
.plan
.clone()
}
};
std::fs::write(env.get_plan_path(), plan.to_string()).unwrap();
std::fs::write(
env.get_plan_path().with_extension("json"),
serde_json::to_string_pretty(&plan).unwrap(),
)
.unwrap();
(seed, env, plan)
} else {
let seed = cli_opts.seed.unwrap_or_else(|| {
let mut rng = rand::rng();
rng.next_u64()
});
tracing::info!("seed={}", seed);
let paths = if let Some(bugbase) = bugbase {
let paths = bugbase.paths(seed);
// Create the output directory if it doesn't exist
if !paths.base.exists() {
std::fs::create_dir_all(&paths.base)
.map_err(|e| format!("{e:?}"))
.unwrap();
}
paths
} else {
let dir = std::env::current_dir().unwrap().join("simulator-output");
std::fs::create_dir_all(&dir).unwrap();
Paths::new(&dir)
};
let mut env = SimulatorEnv::new(seed, cli_opts, paths, SimulationType::Default, profile);
tracing::info!("Generating database interaction plan...");
let plan = InteractionPlan::init_plan(&mut env);
(seed, env, plan)
}
}
fn run_simulation(
env: Arc<Mutex<SimulatorEnv>>,
plan: impl InteractionPlanIterator,
last_execution: Arc<Mutex<Execution>>,
) -> ExecutionResult {
let simulation_type = {
env.clear_poison();
let mut env = env.lock().unwrap();
env.clear();
env.type_
};
match simulation_type {
SimulationType::Default => run_simulation_default(env, plan, last_execution),
SimulationType::Differential => {
let limbo_env = {
let env = env.lock().unwrap();
env.clone_as(SimulationType::Default)
};
let limbo_env = Arc::new(Mutex::new(limbo_env));
differential::run_simulation(limbo_env, env, plan, last_execution)
}
SimulationType::Doublecheck => {
let limbo_env = {
let env = env.lock().unwrap();
env.clone_as(SimulationType::Default)
};
let limbo_env = Arc::new(Mutex::new(limbo_env));
doublecheck::run_simulation(limbo_env, env, plan, last_execution)
}
}
}
fn run_simulation_default(
env: Arc<Mutex<SimulatorEnv>>,
plan: impl InteractionPlanIterator,
last_execution: Arc<Mutex<Execution>>,
) -> ExecutionResult {
tracing::info!("Executing database interaction plan...");
let num_conns = {
let env = env.lock().unwrap();
env.connections.len()
};
let mut conn_states = (0..num_conns)
.map(|_| ConnectionState::default())
.collect::<Vec<_>>();
let mut state = InteractionPlanState {
interaction_pointer: 0,
};
let mut result = execute_interactions(
env.clone(),
plan,
&mut state,
&mut conn_states,
last_execution,
);
let env = env.lock().unwrap();
env.io.print_stats();
tracing::info!("Simulation completed");
env.io.persist_files().unwrap();
if result.error.is_none() {
if env.opts.disable_integrity_check {
tracing::info!("skipping integrity check (disabled by configuration)");
} else {
let ic = integrity_check(&env.get_db_path());
if let Err(err) = ic {
tracing::error!("integrity check failed: {}", err);
result.error = Some(turso_core::LimboError::InternalError(err.to_string()));
} else {
tracing::info!("integrity check passed");
}
}
}
result
}
fn init_logger() -> anyhow::Result<()> {
let file = OpenOptions::new()
.create(true)
.write(true)
.truncate(true)
.open("simulator.log")?;
let requires_ansi = std::io::stdout().is_terminal();
tracing_subscriber::registry()
.with(
tracing_subscriber::fmt::layer()
.with_ansi(requires_ansi)
.with_line_number(true)
.without_time()
.with_thread_ids(false),
)
.with(EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info")))
.with(
tracing_subscriber::fmt::layer()
.with_writer(file)
.with_ansi(false)
.fmt_fields(format::PrettyFields::new())
.with_line_number(true)
.without_time()
.with_thread_ids(false)
.map_fmt_fields(|f| f.debug_alt()),
)
.try_init()?;
Ok(())
}
fn banner() {
println!("{BANNER}");
}
const BANNER: &str = r#"
,_______________________________.
| ,___________________________. |
| | | |
| | >HELLO | |
| | | |
| | >A STRANGE GAME. | |
| | >THE ONLY WINNING MOVE IS | |
| | >NOT TO PLAY. | |
| |___________________________| |
| |
| |
`-------------------------------`
| |
|______________|
,______________________.
/ /====================\ \
/ /======================\ \
/____________________________\
\____________________________/
"#;
fn integrity_check(db_path: &Path) -> anyhow::Result<()> {
assert!(db_path.exists());
let conn = rusqlite::Connection::open(db_path)?;
let mut stmt = conn.prepare("SELECT * FROM pragma_integrity_check;")?;
let mut rows = stmt.query(())?;
let mut result: Vec<String> = Vec::new();
while let Some(row) = rows.next()? {
result.push(row.get(0)?);
}
if result.is_empty() {
anyhow::bail!("simulation failed: integrity_check should return `ok` or a list of problems")
}
if !result[0].eq_ignore_ascii_case("ok") {
// Build a list of problems
result.iter_mut().for_each(|row| *row = format!("- {row}"));
anyhow::bail!("simulation failed: {}", result.join("\n"))
}
Ok(())
}