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fix handling of spurious accesses during retag #2694

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Merged
merged 4 commits into from
Nov 27, 2022
Merged

fix handling of spurious accesses during retag #2694

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3b15db8
!Unpin retags must still be reads, to check dereferenceable
RalfJung Nov 26, 2022
528935d
slightly adjust and synchronize Machine passing for SB and DataRace
RalfJung Nov 26, 2022
c75f23d
make Stacked Borrows retags act like data races
RalfJung Nov 26, 2022
776460f
nits
RalfJung Nov 26, 2022
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26 changes: 12 additions & 14 deletions src/concurrency/data_race.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -838,18 +838,18 @@ impl VClockAlloc {
&self,
alloc_id: AllocId,
range: AllocRange,
global: &GlobalState,
thread_mgr: &ThreadManager<'_, '_>,
machine: &MiriMachine<'_, '_>,
) -> InterpResult<'tcx> {
let global = machine.data_race.as_ref().unwrap();
if global.race_detecting() {
let (index, clocks) = global.current_thread_state(thread_mgr);
let (index, clocks) = global.current_thread_state(&machine.threads);
let mut alloc_ranges = self.alloc_ranges.borrow_mut();
for (offset, range) in alloc_ranges.iter_mut(range.start, range.size) {
if let Err(DataRace) = range.read_race_detect(&clocks, index) {
// Report data-race.
return Self::report_data_race(
global,
thread_mgr,
&machine.threads,
range,
"Read",
false,
Expand All @@ -869,17 +869,17 @@ impl VClockAlloc {
alloc_id: AllocId,
range: AllocRange,
write_type: WriteType,
global: &mut GlobalState,
thread_mgr: &ThreadManager<'_, '_>,
machine: &mut MiriMachine<'_, '_>,
) -> InterpResult<'tcx> {
let global = machine.data_race.as_mut().unwrap();
if global.race_detecting() {
let (index, clocks) = global.current_thread_state(thread_mgr);
let (index, clocks) = global.current_thread_state(&machine.threads);
for (offset, range) in self.alloc_ranges.get_mut().iter_mut(range.start, range.size) {
if let Err(DataRace) = range.write_race_detect(&clocks, index, write_type) {
// Report data-race
return Self::report_data_race(
global,
thread_mgr,
&machine.threads,
range,
write_type.get_descriptor(),
false,
Expand All @@ -901,10 +901,9 @@ impl VClockAlloc {
&mut self,
alloc_id: AllocId,
range: AllocRange,
global: &mut GlobalState,
thread_mgr: &ThreadManager<'_, '_>,
machine: &mut MiriMachine<'_, '_>,
) -> InterpResult<'tcx> {
self.unique_access(alloc_id, range, WriteType::Write, global, thread_mgr)
self.unique_access(alloc_id, range, WriteType::Write, machine)
}

/// Detect data-races for an unsynchronized deallocate operation, will not perform
Expand All @@ -915,10 +914,9 @@ impl VClockAlloc {
&mut self,
alloc_id: AllocId,
range: AllocRange,
global: &mut GlobalState,
thread_mgr: &ThreadManager<'_, '_>,
machine: &mut MiriMachine<'_, '_>,
) -> InterpResult<'tcx> {
self.unique_access(alloc_id, range, WriteType::Deallocate, global, thread_mgr)
self.unique_access(alloc_id, range, WriteType::Deallocate, machine)
}
}

Expand Down
40 changes: 7 additions & 33 deletions src/machine.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1003,21 +1003,12 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
range: AllocRange,
) -> InterpResult<'tcx> {
if let Some(data_race) = &alloc_extra.data_race {
data_race.read(
alloc_id,
range,
machine.data_race.as_ref().unwrap(),
&machine.threads,
)?;
data_race.read(alloc_id, range, machine)?;
}
if let Some(stacked_borrows) = &alloc_extra.stacked_borrows {
stacked_borrows.borrow_mut().before_memory_read(
alloc_id,
prov_extra,
range,
machine.stacked_borrows.as_ref().unwrap(),
machine,
)?;
stacked_borrows
.borrow_mut()
.before_memory_read(alloc_id, prov_extra, range, machine)?;
}
if let Some(weak_memory) = &alloc_extra.weak_memory {
weak_memory.memory_accessed(range, machine.data_race.as_ref().unwrap());
Expand All @@ -1034,21 +1025,10 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
range: AllocRange,
) -> InterpResult<'tcx> {
if let Some(data_race) = &mut alloc_extra.data_race {
data_race.write(
alloc_id,
range,
machine.data_race.as_mut().unwrap(),
&machine.threads,
)?;
data_race.write(alloc_id, range, machine)?;
}
if let Some(stacked_borrows) = &mut alloc_extra.stacked_borrows {
stacked_borrows.get_mut().before_memory_write(
alloc_id,
prov_extra,
range,
machine.stacked_borrows.as_ref().unwrap(),
machine,
)?;
stacked_borrows.get_mut().before_memory_write(alloc_id, prov_extra, range, machine)?;
}
if let Some(weak_memory) = &alloc_extra.weak_memory {
weak_memory.memory_accessed(range, machine.data_race.as_ref().unwrap());
Expand All @@ -1068,19 +1048,13 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
machine.emit_diagnostic(NonHaltingDiagnostic::FreedAlloc(alloc_id));
}
if let Some(data_race) = &mut alloc_extra.data_race {
data_race.deallocate(
alloc_id,
range,
machine.data_race.as_mut().unwrap(),
&machine.threads,
)?;
data_race.deallocate(alloc_id, range, machine)?;
}
if let Some(stacked_borrows) = &mut alloc_extra.stacked_borrows {
stacked_borrows.get_mut().before_memory_deallocation(
alloc_id,
prove_extra,
range,
machine.stacked_borrows.as_ref().unwrap(),
machine,
)
} else {
Expand Down
19 changes: 13 additions & 6 deletions src/stacked_borrows/diagnostics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -353,10 +353,12 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {

/// Report a descriptive error when `new` could not be granted from `derived_from`.
#[inline(never)] // This is only called on fatal code paths
pub(super) fn grant_error(&self, perm: Permission, stack: &Stack) -> InterpError<'tcx> {
pub(super) fn grant_error(&self, stack: &Stack) -> InterpError<'tcx> {
let Operation::Retag(op) = &self.operation else {
unreachable!("grant_error should only be called during a retag")
};
let perm =
op.permission.expect("`start_grant` must be called before calling `grant_error`");
let action = format!(
"trying to retag from {:?} for {:?} permission at {:?}[{:#x}]",
op.orig_tag,
Expand All @@ -374,8 +376,11 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
/// Report a descriptive error when `access` is not permitted based on `tag`.
#[inline(never)] // This is only called on fatal code paths
pub(super) fn access_error(&self, stack: &Stack) -> InterpError<'tcx> {
let Operation::Access(op) = &self.operation else {
unreachable!("access_error should only be called during an access")
// Deallocation and retagging also do an access as part of their thing, so handle that here, too.
let op = match &self.operation {
Operation::Access(op) => op,
Operation::Retag(_) => return self.grant_error(stack),
Operation::Dealloc(_) => return self.dealloc_error(stack),
};
let action = format!(
"attempting a {access} using {tag:?} at {alloc_id:?}[{offset:#x}]",
Expand Down Expand Up @@ -428,14 +433,16 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
}

#[inline(never)] // This is only called on fatal code paths
pub fn dealloc_error(&self) -> InterpError<'tcx> {
pub fn dealloc_error(&self, stack: &Stack) -> InterpError<'tcx> {
let Operation::Dealloc(op) = &self.operation else {
unreachable!("dealloc_error should only be called during a deallocation")
};
err_sb_ub(
format!(
"no item granting write access for deallocation to tag {:?} at {:?} found in borrow stack",
op.tag, self.history.id,
"attempting deallocation using {tag:?} at {alloc_id:?}{cause}",
tag = op.tag,
alloc_id = self.history.id,
cause = error_cause(stack, op.tag),
),
None,
op.tag.and_then(|tag| self.get_logs_relevant_to(tag, None)),
Expand Down
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