diff --git a/src/data_race.rs b/src/data_race.rs index ba730037456..5a6dd1d81d0 100644 --- a/src/data_race.rs +++ b/src/data_race.rs @@ -437,6 +437,49 @@ impl MemoryCellClocks { /// Evaluation context extensions. impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {} pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> { + /// Temporarily allow data-races to occur. This should only be used in + /// one of these cases: + /// - One of the appropriate `validate_atomic` functions will be called to + /// to treat a memory access as atomic. + /// - The memory being accessed should be treated as internal state, that + /// cannot be accessed by the interpreted program. + /// - Execution of the interpreted program execution has halted. + #[inline] + fn allow_data_races_ref(&self, op: impl FnOnce(&MiriEvalContext<'mir, 'tcx>) -> R) -> R { + let this = self.eval_context_ref(); + let old = if let Some(data_race) = &this.machine.data_race { + data_race.multi_threaded.replace(false) + } else { + false + }; + let result = op(this); + if let Some(data_race) = &this.machine.data_race { + data_race.multi_threaded.set(old); + } + result + } + + /// Same as `allow_data_races_ref`, this temporarily disables any data-race detection and + /// so should only be used for atomic operations or internal state that the program cannot + /// access. + #[inline] + fn allow_data_races_mut( + &mut self, + op: impl FnOnce(&mut MiriEvalContext<'mir, 'tcx>) -> R, + ) -> R { + let this = self.eval_context_mut(); + let old = if let Some(data_race) = &this.machine.data_race { + data_race.multi_threaded.replace(false) + } else { + false + }; + let result = op(this); + if let Some(data_race) = &this.machine.data_race { + data_race.multi_threaded.set(old); + } + result + } + /// Atomic variant of read_scalar_at_offset. fn read_scalar_at_offset_atomic( &self, @@ -927,47 +970,6 @@ impl VClockAlloc { impl<'mir, 'tcx: 'mir> EvalContextPrivExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {} trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> { - // Temporarily allow data-races to occur, this should only be - // used if either one of the appropriate `validate_atomic` functions - // will be called to treat a memory access as atomic or if the memory - // being accessed should be treated as internal state, that cannot be - // accessed by the interpreted program. - #[inline] - fn allow_data_races_ref(&self, op: impl FnOnce(&MiriEvalContext<'mir, 'tcx>) -> R) -> R { - let this = self.eval_context_ref(); - let old = if let Some(data_race) = &this.machine.data_race { - data_race.multi_threaded.replace(false) - } else { - false - }; - let result = op(this); - if let Some(data_race) = &this.machine.data_race { - data_race.multi_threaded.set(old); - } - result - } - - /// Same as `allow_data_races_ref`, this temporarily disables any data-race detection and - /// so should only be used for atomic operations or internal state that the program cannot - /// access. - #[inline] - fn allow_data_races_mut( - &mut self, - op: impl FnOnce(&mut MiriEvalContext<'mir, 'tcx>) -> R, - ) -> R { - let this = self.eval_context_mut(); - let old = if let Some(data_race) = &this.machine.data_race { - data_race.multi_threaded.replace(false) - } else { - false - }; - let result = op(this); - if let Some(data_race) = &this.machine.data_race { - data_race.multi_threaded.set(old); - } - result - } - /// Generic atomic operation implementation fn validate_atomic_op( &self, diff --git a/src/eval.rs b/src/eval.rs index 5f6348fe0bd..c4d58eb7714 100644 --- a/src/eval.rs +++ b/src/eval.rs @@ -344,7 +344,12 @@ pub fn eval_entry<'tcx>( })(); // Machine cleanup. - EnvVars::cleanup(&mut ecx).unwrap(); + // Execution of the program has halted so any memory access we do here + // cannot produce a real data race. If we do not do something to disable + // data race detection here, some uncommon combination of errors will + // cause a data race to be detected: + // https://github.com/rust-lang/miri/issues/2020 + ecx.allow_data_races_mut(|ecx| EnvVars::cleanup(ecx).unwrap()); // Process the result. match res {