miri does not support parking_lot (requires futexes: syscall ID 202)

[ralpha]

I'm testing out miri on my codebase. (So not very familiar with it)
Given this is much higher level then some small library, so did not expect it to work 2nd try.
This test failed because of unsupported operation: miri does not support syscall ID 202.
It was trying to connect to a SQLite database (via Diesel).

let mut builder = r2d2::Pool::builder();
let pool_result = builder.build(manager); // <<---Error from here

Maybe you can do something with this info.
So call is going: MyApplication -> (diesel ->) r2d2 -> parking_lot -> parking_lot_core -> Error

error: unsupported operation: miri does not support syscall ID 202
   --> /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot_core-0.8.0/src/thread_parker/linux.rs:112:13
    |
112 | /             libc::syscall(
113 | |                 libc::SYS_futex,
114 | |                 &self.futex,
115 | |                 libc::FUTEX_WAIT | libc::FUTEX_PRIVATE_FLAG,
116 | |                 1,
117 | |                 ts_ptr,
118 | |             )
    | |_____________^ miri does not support syscall ID 202
    |
    = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
            
    = note: inside `parking_lot_core::thread_parker::imp::ThreadParker::futex_wait` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot_core-0.8.0/src/thread_parker/linux.rs:112:13
    = note: inside `<parking_lot_core::thread_parker::imp::ThreadParker as parking_lot_core::thread_parker::ThreadParkerT>::park_until` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot_core-0.8.0/src/thread_parker/linux.rs:87:13
    = note: inside closure at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot_core-0.8.0/src/parking_lot.rs:650:30
    = note: inside `parking_lot_core::parking_lot::with_thread_data::<parking_lot_core::parking_lot::ParkResult, [closure@parking_lot_core::parking_lot::park::{{closure}}#0 0:&usize, 1:[closure@parking_lot::condvar::Condvar::wait_until_internal::{{closure}}#0 0:&&parking_lot::condvar::Condvar, 1:&*mut parking_lot::raw_mutex::RawMutex, 2:&mut bool], 2:&std::option::Option<std::time::Instant>, 3:&parking_lot_core::parking_lot::ParkToken, 4:[closure@parking_lot::condvar::Condvar::wait_until_internal::{{closure}}#1 0:&&parking_lot::raw_mutex::RawMutex], 5:[closure@parking_lot::condvar::Condvar::wait_until_internal::{{closure}}#2 0:&usize, 1:&mut bool, 2:&&parking_lot::condvar::Condvar]]>` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot_core-0.8.0/src/parking_lot.rs:224:5
    = note: inside `parking_lot_core::parking_lot::park::<[closure@parking_lot::condvar::Condvar::wait_until_internal::{{closure}}#0 0:&&parking_lot::condvar::Condvar, 1:&*mut parking_lot::raw_mutex::RawMutex, 2:&mut bool], [closure@parking_lot::condvar::Condvar::wait_until_internal::{{closure}}#1 0:&&parking_lot::raw_mutex::RawMutex], [closure@parking_lot::condvar::Condvar::wait_until_internal::{{closure}}#2 0:&usize, 1:&mut bool, 2:&&parking_lot::condvar::Condvar]>` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot_core-0.8.0/src/parking_lot.rs:617:5
    = note: inside `parking_lot::condvar::Condvar::wait_until_internal` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot-0.11.0/src/condvar.rs:338:26
    = note: inside `parking_lot::condvar::Condvar::wait_until::<r2d2::PoolInternals<diesel::sqlite::connection::SqliteConnection>>` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/parking_lot-0.11.0/src/condvar.rs:292:9
    = note: inside `r2d2::Pool::<diesel::r2d2::ConnectionManager<diesel::sqlite::connection::SqliteConnection>>::wait_for_initialization` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/r2d2-0.8.9/src/lib.rs:398:16
    = note: inside `r2d2::config::Builder::<diesel::r2d2::ConnectionManager<diesel::sqlite::connection::SqliteConnection>>::build` at /home/username/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/r2d2-0.8.9/src/config.rs:228:9

For now I'll be adding #[cfg_attr(miri, ignore)].

[oli-obk]

we don't support network connections yet at all. We should look into supporting parking_lot though, that seems like a good first step

[RalfJung]

SQLite doesn't need a network connection I think, usually applications open the DB files directly.

But yeah, looks like for parking_lot we'll need to implement futexes.

[RalfJung]

Looks like Miri now needs this even for the standard library due to rust-lang/rust#76919 (Cc rust-lang/rust#77406).

@m-ou-se said they would work on it; let me know if you need any help!

[ralpha]

I have to say, this was resolved very quick! Great work! @m-ou-se @RalfJung

[RalfJung]

You were quite lucky, the standard library started using futexes so there was a lot of pressure to get them working. ;) Then @m-ou-se went above what the standard library needed and also got parking_lot to work.