Allow backtraces to cross thread boundaries

src/concurrency/thread.rs

@@ -235,6 +235,9 @@ pub struct Thread<'tcx> {
     /// The join status.
     join_status: ThreadJoinStatus,
 
+    // ThreadId that spawned this thread and backtrace to where this thread was spawned
+    thread_spawn_context: Option<(ThreadId, Vec<FrameInfo<'tcx>>)>,
+
     /// Stack of active panic payloads for the current thread. Used for storing
     /// the argument of the call to `miri_start_unwind` (the panic payload) when unwinding.
     /// This is pointer-sized, and matches the `Payload` type in `src/libpanic_unwind/miri.rs`.
@@ -321,13 +324,18 @@ impl<'tcx> std::fmt::Debug for Thread<'tcx> {
 }
 
 impl<'tcx> Thread<'tcx> {
-    fn new(name: Option<&str>, on_stack_empty: Option<StackEmptyCallback<'tcx>>) -> Self {
+    fn new(
+        name: Option<&str>,
+        on_stack_empty: Option<StackEmptyCallback<'tcx>>,
+        thread_spawn_context: Option<(ThreadId, Vec<FrameInfo<'tcx>>)>,
+    ) -> Self {
         Self {
             state: ThreadState::Enabled,
             thread_name: name.map(|name| Vec::from(name.as_bytes())),
             stack: Vec::new(),
             top_user_relevant_frame: None,
             join_status: ThreadJoinStatus::Joinable,
+            thread_spawn_context,
             panic_payloads: Vec::new(),
             last_error: None,
             on_stack_empty,
@@ -345,6 +353,7 @@ impl VisitProvenance for Thread<'_> {
             state: _,
             thread_name: _,
             join_status: _,
+            thread_spawn_context: _,
             on_stack_empty: _, // we assume the closure captures no GC-relevant state
         } = self;
 
@@ -475,7 +484,7 @@ impl<'tcx> Default for ThreadManager<'tcx> {
     fn default() -> Self {
         let mut threads = IndexVec::new();
         // Create the main thread and add it to the list of threads.
-        threads.push(Thread::new(Some("main"), None));
+        threads.push(Thread::new(Some("main"), None, None));
         Self {
             active_thread: ThreadId::MAIN_THREAD,
             threads,
@@ -542,9 +551,13 @@ impl<'tcx> ThreadManager<'tcx> {
     }
 
     /// Create a new thread and returns its id.
-    fn create_thread(&mut self, on_stack_empty: StackEmptyCallback<'tcx>) -> ThreadId {
+    fn create_thread(
+        &mut self,
+        on_stack_empty: StackEmptyCallback<'tcx>,
+        thread_spawn_context: Option<(ThreadId, Vec<FrameInfo<'tcx>>)>,
+    ) -> ThreadId {
         let new_thread_id = ThreadId::new(self.threads.len());
-        self.threads.push(Thread::new(None, Some(on_stack_empty)));
+        self.threads.push(Thread::new(None, Some(on_stack_empty), thread_spawn_context));
         new_thread_id
     }
 
@@ -711,6 +724,13 @@ impl<'tcx> ThreadManager<'tcx> {
         self.threads[thread].thread_display_name(thread)
     }
 
+    pub fn get_thread_spawn_context(
+        &self,
+        thread: ThreadId,
+    ) -> Option<&(ThreadId, Vec<FrameInfo<'tcx>>)> {
+        self.threads[thread].thread_spawn_context.as_ref()
+    }
+
     /// Put the thread into the blocked state.
     fn block_thread(
         &mut self,
@@ -924,10 +944,13 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         let this = self.eval_context_mut();
 
         // Create the new thread
-        let new_thread_id = this.machine.threads.create_thread({
-            let mut state = tls::TlsDtorsState::default();
-            Box::new(move |m| state.on_stack_empty(m))
-        });
+        let new_thread_id = this.machine.threads.create_thread(
+            {
+                let mut state = tls::TlsDtorsState::default();
+                Box::new(move |m| state.on_stack_empty(m))
+            },
+            Some((this.machine.threads.active_thread(), this.generate_stacktrace())),
+        );
         let current_span = this.machine.current_span();
         if let Some(data_race) = &mut this.machine.data_race {
             data_race.thread_created(&this.machine.threads, new_thread_id, current_span);

src/diagnostics.rs

@@ -588,6 +588,36 @@ pub fn report_msg<'tcx>(
         }
     }
 
+    // Traverse thread spawns to display thread backtraces up to main thread
+    if let Some(mut thread) = thread {
+        let mut thread_spawn_context = machine.threads.get_thread_spawn_context(thread);
+
+        while let Some((spawning_thread, thread_spawn_backtrace)) = thread_spawn_context {
+            err.note(format!(
+                "thread `{}` was spawned by thread `{}`",
+                machine.threads.get_thread_display_name(thread),
+                machine.threads.get_thread_display_name(*spawning_thread)
+            ));
+            let (pruned_stacktrace, _was_pruned) =
+                prune_stacktrace(thread_spawn_backtrace.to_vec(), machine);
+
+            for (idx, frame_info) in pruned_stacktrace.iter().enumerate() {
+                let is_local = machine.is_local(frame_info);
+                // No span for non-local frames except the first frame (which is the error site).
+                if is_local && idx > 0 {
+                    err.subdiagnostic(frame_info.as_note(machine.tcx));
+                } else {
+                    let sm = sess.source_map();
+                    let span = sm.span_to_embeddable_string(frame_info.span);
+                    err.note(format!("{frame_info} at {span}"));
+                }
+            }
+
+            thread = *spawning_thread;
+            thread_spawn_context = machine.threads.get_thread_spawn_context(thread);
+        }
+    }
+
     err.emit();
 }
 

tests/fail-dep/concurrency/libc_pthread_create_too_few_args.stderr

@@ -5,6 +5,8 @@ error: Undefined Behavior: calling a function with more arguments than it expect
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_create_too_few_args.rs:LL:CC
 
 error: aborting due to 1 previous error
 

tests/fail-dep/concurrency/libc_pthread_create_too_many_args.stderr

@@ -5,6 +5,8 @@ error: Undefined Behavior: calling a function with fewer arguments than it requi
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_create_too_many_args.rs:LL:CC
 
 error: aborting due to 1 previous error
 

tests/fail-dep/concurrency/libc_pthread_join_main.stderr

@@ -8,6 +8,22 @@ LL |             assert_eq!(libc::pthread_join(thread_id, ptr::null_mut()), 0);
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC
+   |
+LL |       let handle = thread::spawn(move || {
+   |  __________________^
+LL | |         unsafe {
+LL | |             assert_eq!(libc::pthread_join(thread_id, ptr::null_mut()), 0);
+LL | |         }
+LL | |     });
+   | |______^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail-dep/concurrency/libc_pthread_join_multiple.stderr

@@ -8,6 +8,20 @@ LL | ...   assert_eq!(libc::pthread_join(native_copy, ptr::null_mut()), 0);
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC
+   |
+LL |   ...   let handle = thread::spawn(move || {
+   |  ____________________^
+LL | | ...       assert_eq!(libc::pthread_join(native_copy, ptr::null_mut()), 0);
+LL | | ...   });
+   | |________^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail-dep/concurrency/libc_pthread_join_self.stderr

@@ -8,6 +8,23 @@ LL |             assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC
+   |
+LL |       let handle = thread::spawn(|| {
+   |  __________________^
+LL | |         unsafe {
+LL | |             let native: libc::pthread_t = libc::pthread_self();
+LL | |             assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+LL | |         }
+LL | |     });
+   | |______^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.stderr

@@ -6,6 +6,19 @@ LL |             assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _
    |
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC
+   |
+LL | /         thread::spawn(move || {
+LL | |             assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _), 0);
+LL | |         })
+   | |__________^
 
 error: deadlock: the evaluated program deadlocked
   --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC

tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.stderr

@@ -8,6 +8,19 @@ LL | ...t_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0);
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC
+   |
+LL | / ...   thread::spawn(move || {
+LL | | ...       assert_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0);
+LL | | ...   })
+   | |________^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.stderr

@@ -8,6 +8,19 @@ LL | ...   assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _),
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC
+   |
+LL | / ...   thread::spawn(move || {
+LL | | ...       assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _), 0);
+LL | | ...   })
+   | |________^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.stderr

@@ -6,6 +6,19 @@ LL |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mu
    |
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC
+   |
+LL | /         thread::spawn(move || {
+LL | |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mut _), 0);
+LL | |         })
+   | |__________^
 
 error: deadlock: the evaluated program deadlocked
   --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC

tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.stderr

@@ -6,6 +6,19 @@ LL |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mu
    |
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC
+   = note: thread `unnamed-ID` was spawned by thread `main`
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::new` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked_::<'_, {closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn_unchecked::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::Builder::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::spawn::<{closure@tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> tests/fail-dep/concurrency/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC
+   |
+LL | /         thread::spawn(move || {
+LL | |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mut _), 0);
+LL | |         })
+   | |__________^
 
 error: deadlock: the evaluated program deadlocked
   --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC