deadlock: show backtrace for all threads

RalfJung · RalfJung · commit 923906e274df · 2024-04-16T13:06:19.000+02:00
diff --git a/src/borrow_tracker/stacked_borrows/diagnostics.rs b/src/borrow_tracker/stacked_borrows/diagnostics.rs
@@ -438,7 +438,7 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
             .machine
             .threads
             .all_stacks()
-            .flatten()
+            .flat_map(|(_id, stack)| stack)
             .map(|frame| {
                 frame.extra.borrow_tracker.as_ref().expect("we should have borrow tracking data")
             })
diff --git a/src/concurrency/thread.rs b/src/concurrency/thread.rs
@@ -430,11 +430,10 @@ impl<'mir, 'tcx: 'mir> ThreadManager<'mir, 'tcx> {
     ) -> &mut Vec<Frame<'mir, 'tcx, Provenance, FrameExtra<'tcx>>> {
         &mut self.threads[self.active_thread].stack
     }
-
     pub fn all_stacks(
         &self,
-    ) -> impl Iterator<Item = &[Frame<'mir, 'tcx, Provenance, FrameExtra<'tcx>>]> {
-        self.threads.iter().map(|t| &t.stack[..])
+    ) -> impl Iterator<Item = (ThreadId, &[Frame<'mir, 'tcx, Provenance, FrameExtra<'tcx>>])> {
+        self.threads.iter_enumerated().map(|(id, t)| (id, &t.stack[..]))
     }
 
     /// Create a new thread and returns its id.
diff --git a/src/diagnostics.rs b/src/diagnostics.rs
@@ -361,9 +361,12 @@ pub fn report_error<'tcx, 'mir>(
     };
 
     let stacktrace = ecx.generate_stacktrace();
-    let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
+    let (stacktrace, mut any_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
 
-    // We want to dump the allocation if this is `InvalidUninitBytes`. Since `format_error` consumes `e`, we compute the outut early.
+    let mut show_all_threads = false;
+
+    // We want to dump the allocation if this is `InvalidUninitBytes`.
+    // Since `format_interp_error` consumes `e`, we compute the outut early.
     let mut extra = String::new();
     match e.kind() {
         UndefinedBehavior(InvalidUninitBytes(Some((alloc_id, access)))) => {
@@ -375,6 +378,15 @@ pub fn report_error<'tcx, 'mir>(
             .unwrap();
             writeln!(extra, "{:?}", ecx.dump_alloc(*alloc_id)).unwrap();
         }
+        MachineStop(info) => {
+            let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
+            match info {
+                TerminationInfo::Deadlock => {
+                    show_all_threads = true;
+                }
+                _ => {}
+            }
+        }
         _ => {}
     }
 
@@ -387,18 +399,39 @@ pub fn report_error<'tcx, 'mir>(
         vec![],
         helps,
         &stacktrace,
+        Some(ecx.get_active_thread()),
         &ecx.machine,
     );
 
+    eprint!("{extra}"); // newlines are already in the string
+
+    if show_all_threads {
+        for (thread, stack) in ecx.machine.threads.all_stacks() {
+            if thread != ecx.get_active_thread() {
+                let stacktrace = Frame::generate_stacktrace_from_stack(stack);
+                let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
+                any_pruned |= was_pruned;
+                report_msg(
+                    DiagLevel::Error,
+                    format!("deadlock: the evaluated program deadlocked"),
+                    vec![format!("the evaluated program deadlocked")],
+                    vec![],
+                    vec![],
+                    &stacktrace,
+                    Some(thread),
+                    &ecx.machine,
+                )
+            }
+        }
+    }
+
     // Include a note like `std` does when we omit frames from a backtrace
-    if was_pruned {
+    if any_pruned {
         ecx.tcx.dcx().note(
             "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
         );
     }
 
-    eprint!("{extra}"); // newlines are already in the string
-
     // Debug-dump all locals.
     for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
         trace!("-------------------");
@@ -435,6 +468,7 @@ pub fn report_leaks<'mir, 'tcx>(
             vec![],
             vec![],
             &backtrace,
+            None, // we don't know the thread this is from
             &ecx.machine,
         );
     }
@@ -445,6 +479,24 @@ pub fn report_leaks<'mir, 'tcx>(
     }
 }
 
+fn emit_stacktrace<'tcx>(
+    stacktrace: &[FrameInfo<'tcx>],
+    machine: &MiriMachine<'_, 'tcx>,
+    err: &mut Diag<'_, ()>,
+) {
+    for (idx, frame_info) in stacktrace.iter().enumerate() {
+        let is_local = machine.is_local(frame_info);
+        // No span for non-local frames and the first frame (which is the error site).
+        if is_local && idx > 0 {
+            err.subdiagnostic(err.dcx, frame_info.as_note(machine.tcx));
+        } else {
+            let sm = machine.tcx.sess.source_map();
+            let span = sm.span_to_embeddable_string(frame_info.span);
+            err.note(format!("{frame_info} at {span}"));
+        }
+    }
+}
+
 /// Report an error or note (depending on the `error` argument) with the given stacktrace.
 /// Also emits a full stacktrace of the interpreter stack.
 /// We want to present a multi-line span message for some errors. Diagnostics do not support this
@@ -457,6 +509,7 @@ pub fn report_msg<'tcx>(
     notes: Vec<(Option<SpanData>, String)>,
     helps: Vec<(Option<SpanData>, String)>,
     stacktrace: &[FrameInfo<'tcx>],
+    thread: Option<ThreadId>,
     machine: &MiriMachine<'_, 'tcx>,
 ) {
     let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
@@ -502,29 +555,22 @@ pub fn report_msg<'tcx>(
     }
 
     // Add backtrace
+    // Compute backtrace title.
     let mut backtrace_title = String::from("BACKTRACE");
     if extra_span {
         write!(backtrace_title, " (of the first span)").unwrap();
     }
-    let thread_name =
-        machine.threads.get_thread_display_name(machine.threads.get_active_thread_id());
-    if thread_name != "main" {
-        // Only print thread name if it is not `main`.
-        write!(backtrace_title, " on thread `{thread_name}`").unwrap();
-    };
+    if let Some(thread) = thread {
+        let thread_name = machine.threads.get_thread_display_name(thread);
+        if thread_name != "main" {
+            // Only print thread name if it is not `main`.
+            write!(backtrace_title, " on thread `{thread_name}`").unwrap();
+        };
+    }
     write!(backtrace_title, ":").unwrap();
     err.note(backtrace_title);
-    for (idx, frame_info) in stacktrace.iter().enumerate() {
-        let is_local = machine.is_local(frame_info);
-        // No span for non-local frames and the first frame (which is the error site).
-        if is_local && idx > 0 {
-            err.subdiagnostic(err.dcx, 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}"));
-        }
-    }
+    // Add backtrace itself.
+    emit_stacktrace(stacktrace, machine, &mut err);
 
     err.emit();
 }
@@ -628,7 +674,16 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
             _ => vec![],
         };
 
-        report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
+        report_msg(
+            diag_level,
+            title,
+            vec![msg],
+            notes,
+            helps,
+            &stacktrace,
+            Some(self.threads.get_active_thread_id()),
+            self,
+        );
     }
 }
 
@@ -654,6 +709,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             vec![],
             vec![],
             &stacktrace,
+            Some(this.get_active_thread()),
             &this.machine,
         );
     }
diff --git a/tests/fail-dep/shims/sync/libc_pthread_mutex_deadlock.rs b/tests/fail-dep/shims/sync/libc_pthread_mutex_deadlock.rs
@@ -1,4 +1,5 @@
 //@ignore-target-windows: No libc on Windows
+//@error-in-other-file: deadlock
 
 use std::cell::UnsafeCell;
 use std::sync::Arc;
diff --git a/tests/fail-dep/shims/sync/libc_pthread_mutex_deadlock.stderr b/tests/fail-dep/shims/sync/libc_pthread_mutex_deadlock.stderr
@@ -7,7 +7,26 @@ LL |             assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at $DIR/libc_pthread_mutex_deadlock.rs:LL:CC
 
+error: deadlock: the evaluated program deadlocked
+  --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   |
+LL |             let ret = libc::pthread_join(self.id, ptr::null_mut());
+   |                                                                  ^ the evaluated program deadlocked
+   |
+   = note: BACKTRACE:
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::join` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::JoinInner::<'_, ()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::JoinHandle::<()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> $DIR/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 | |         })
+LL | |         .join()
+   | |_______________^
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
diff --git a/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_read_deadlock.rs b/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_read_deadlock.rs
@@ -1,4 +1,5 @@
 //@ignore-target-windows: No libc on Windows
+//@error-in-other-file: deadlock
 
 use std::cell::UnsafeCell;
 use std::sync::Arc;
diff --git a/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_read_deadlock.stderr b/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_read_deadlock.stderr
@@ -7,7 +7,26 @@ LL |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mu
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at $DIR/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC
 
+error: deadlock: the evaluated program deadlocked
+  --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   |
+LL |             let ret = libc::pthread_join(self.id, ptr::null_mut());
+   |                                                                  ^ the evaluated program deadlocked
+   |
+   = note: BACKTRACE:
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::join` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::JoinInner::<'_, ()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::JoinHandle::<()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> $DIR/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 | |         })
+LL | |         .join()
+   | |_______________^
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
diff --git a/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_write_deadlock.rs b/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_write_deadlock.rs
@@ -1,4 +1,5 @@
 //@ignore-target-windows: No libc on Windows
+//@error-in-other-file: deadlock
 
 use std::cell::UnsafeCell;
 use std::sync::Arc;
diff --git a/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_write_deadlock.stderr b/tests/fail-dep/shims/sync/libc_pthread_rwlock_write_write_deadlock.stderr
@@ -7,7 +7,26 @@ LL |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mu
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at $DIR/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC
 
+error: deadlock: the evaluated program deadlocked
+  --> RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   |
+LL |             let ret = libc::pthread_join(self.id, ptr::null_mut());
+   |                                                                  ^ the evaluated program deadlocked
+   |
+   = note: BACKTRACE:
+   = note: inside `std::sys::pal::PLATFORM::thread::Thread::join` at RUSTLIB/std/src/sys/pal/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::JoinInner::<'_, ()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::JoinHandle::<()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main`
+  --> $DIR/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 | |         })
+LL | |         .join()
+   | |_______________^
+
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 

Original file line number	Diff line number	Diff line change
`@@ -430,11 +430,10 @@ impl<'mir, 'tcx: 'mir> ThreadManager<'mir, 'tcx> {`
`430`	`430`	`) -> &mut Vec<Frame<'mir, 'tcx, Provenance, FrameExtra<'tcx>>> {`
`431`	`431`	`&mut self.threads[self.active_thread].stack`
`432`	`432`	`}`
`433`		`-`
`434`	`433`	`pub fn all_stacks(`
`435`	`434`	`&self,`
`436`		`- ) -> impl Iterator<Item = &[Frame<'mir, 'tcx, Provenance, FrameExtra<'tcx>>]> {`
`437`		`- self.threads.iter().map(\|t\| &t.stack[..])`
	`435`	`+ ) -> impl Iterator<Item = (ThreadId, &[Frame<'mir, 'tcx, Provenance, FrameExtra<'tcx>>])> {`
	`436`	`+ self.threads.iter_enumerated().map(\|(id, t)\| (id, &t.stack[..]))`
`438`	`437`	`}`
`439`	`438`
`440`	`439`	`/// Create a new thread and returns its id.`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`//@ignore-target-windows: No libc on Windows`
	`2`	`+//@error-in-other-file: deadlock`
`2`	`3`
`3`	`4`	`use std::cell::UnsafeCell;`
`4`	`5`	`use std::sync::Arc;`