rust-lang · RalfJung · Oct 30, 2025 · Oct 30, 2025 · Oct 30, 2025
diff --git a/README.md b/README.md
@@ -292,6 +292,9 @@ Try running `cargo miri clean`.
 Miri adds its own set of `-Z` flags, which are usually set via the `MIRIFLAGS`
 environment variable. We first document the most relevant and most commonly used flags:
 
+* `-Zmiri-backtrace=<0|1|full>` configures how Miri prints backtraces: `1` is the default,
+  where backtraces are printed in pruned form; `full` prints backtraces without pruning, and `0`
+  disables backtraces entirely.
 * `-Zmiri-deterministic-concurrency` makes Miri's concurrency-related behavior fully deterministic.
   Strictly speaking, Miri is always fully deterministic when isolation is enabled (the default
   mode), but this determinism is achieved by using an RNG with a fixed seed. Seemingly harmless

diff --git a/src/diagnostics.rs b/src/diagnostics.rs
@@ -128,7 +128,7 @@ pub enum NonHaltingDiagnostic {
     PoppedPointerTag(Item, String),
     TrackingAlloc(AllocId, Size, Align),
     FreedAlloc(AllocId),
-    AccessedAlloc(AllocId, AccessKind),
+    AccessedAlloc(AllocId, AllocRange, AccessKind),
     RejectedIsolatedOp(String),
     ProgressReport {
         block_count: u64, // how many basic blocks have been run so far
@@ -604,28 +604,30 @@ pub fn report_msg<'tcx>(
     }
 
     // Add backtrace
-    let mut backtrace_title = String::from("BACKTRACE");
-    if extra_span {
-        write!(backtrace_title, " (of the first span)").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(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}"));
+    if stacktrace.len() > 1 {
+        let mut backtrace_title = String::from("BACKTRACE");
+        if extra_span {
+            write!(backtrace_title, " (of the first span)").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(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}"));
+            }
         }
     }
 
@@ -673,15 +675,15 @@ impl<'tcx> MiriMachine<'tcx> {
                     "created tag {tag:?} with {perm} at {alloc_id:?}{range:?} derived from {orig_tag:?}"
                 ),
             PoppedPointerTag(item, cause) => format!("popped tracked tag for item {item:?}{cause}"),
-            TrackingAlloc(AllocId(id), size, align) =>
+            TrackingAlloc(id, size, align) =>
                 format!(
-                    "now tracking allocation of {size} bytes (alignment {align} bytes) with id {id}",
+                    "now tracking allocation {id:?} of {size} bytes (alignment {align} bytes)",
                     size = size.bytes(),
                     align = align.bytes(),
                 ),
-            AccessedAlloc(AllocId(id), access_kind) =>
-                format!("{access_kind} to allocation with id {id}"),
-            FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
+            AccessedAlloc(id, range, access_kind) =>
+                format!("{access_kind} at {id:?}[{}..{}]", range.start.bytes(), range.end().bytes()),
+            FreedAlloc(id) => format!("freed allocation {id:?}"),
             RejectedIsolatedOp(op) => format!("{op} was made to return an error due to isolation"),
             ProgressReport { .. } =>
                 format!("progress report: current operation being executed is here"),

diff --git a/src/machine.rs b/src/machine.rs
@@ -1523,8 +1523,11 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
         range: AllocRange,
     ) -> InterpResult<'tcx> {
         if machine.track_alloc_accesses && machine.tracked_alloc_ids.contains(&alloc_id) {
-            machine
-                .emit_diagnostic(NonHaltingDiagnostic::AccessedAlloc(alloc_id, AccessKind::Read));
+            machine.emit_diagnostic(NonHaltingDiagnostic::AccessedAlloc(
+                alloc_id,
+                range,
+                AccessKind::Read,
+            ));
         }
         // The order of checks is deliberate, to prefer reporting a data race over a borrow tracker error.
         match &machine.data_race {
@@ -1559,8 +1562,11 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
         range: AllocRange,
     ) -> InterpResult<'tcx> {
         if machine.track_alloc_accesses && machine.tracked_alloc_ids.contains(&alloc_id) {
-            machine
-                .emit_diagnostic(NonHaltingDiagnostic::AccessedAlloc(alloc_id, AccessKind::Write));
+            machine.emit_diagnostic(NonHaltingDiagnostic::AccessedAlloc(
+                alloc_id,
+                range,
+                AccessKind::Write,
+            ));
         }
         match &machine.data_race {
             GlobalDataRaceHandler::None => {}

diff --git a/tests/fail-dep/concurrency/apple_os_unfair_lock_assert_not_owner.stderr b/tests/fail-dep/concurrency/apple_os_unfair_lock_assert_not_owner.stderr
@@ -3,9 +3,6 @@ error: abnormal termination: called os_unfair_lock_assert_not_owner on an os_unf
    |
 LL |         libc::os_unfair_lock_assert_not_owner(lock.get());
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ abnormal termination occurred here
-   |
-   = note: BACKTRACE:
-   = note: inside `main` at tests/fail-dep/concurrency/apple_os_unfair_lock_assert_not_owner.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/apple_os_unfair_lock_assert_owner.stderr b/tests/fail-dep/concurrency/apple_os_unfair_lock_assert_owner.stderr
@@ -3,9 +3,6 @@ error: abnormal termination: called os_unfair_lock_assert_owner on an os_unfair_
    |
 LL |         libc::os_unfair_lock_assert_owner(lock.get());
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ abnormal termination occurred here
-   |
-   = note: BACKTRACE:
-   = note: inside `main` at tests/fail-dep/concurrency/apple_os_unfair_lock_assert_owner.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/apple_os_unfair_lock_move_deadlock.stderr b/tests/fail-dep/concurrency/apple_os_unfair_lock_move_deadlock.stderr
@@ -3,9 +3,6 @@ error: the evaluated program deadlocked
    |
 LL |     unsafe { libc::os_unfair_lock_lock(lock.get()) };
    |                                                  ^ this thread got stuck here
-   |
-   = note: BACKTRACE:
-   = note: inside `main` at tests/fail-dep/concurrency/apple_os_unfair_lock_move_deadlock.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/apple_os_unfair_lock_reentrant.stderr b/tests/fail-dep/concurrency/apple_os_unfair_lock_reentrant.stderr
@@ -3,9 +3,6 @@ error: abnormal termination: attempted to lock an os_unfair_lock that is already
    |
 LL |         libc::os_unfair_lock_lock(lock.get());
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ abnormal termination occurred here
-   |
-   = note: BACKTRACE:
-   = note: inside `main` at tests/fail-dep/concurrency/apple_os_unfair_lock_reentrant.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/apple_os_unfair_lock_unowned.stderr b/tests/fail-dep/concurrency/apple_os_unfair_lock_unowned.stderr
@@ -3,9 +3,6 @@ error: abnormal termination: attempted to unlock an os_unfair_lock not owned by
    |
 LL |         libc::os_unfair_lock_unlock(lock.get());
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ abnormal termination occurred here
-   |
-   = note: BACKTRACE:
-   = note: inside `main` at tests/fail-dep/concurrency/apple_os_unfair_lock_unowned.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr b/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_cond_destroy(cond.as_mut_ptr());
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs:LL:CC
 
 Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
 ALLOC DUMP

diff --git a/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr b/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_condattr_destroy(attr.as_mut_ptr());
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs:LL:CC
 
 Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
 ALLOC DUMP

diff --git a/tests/fail-dep/concurrency/libc_pthread_create_too_few_args.stderr b/tests/fail-dep/concurrency/libc_pthread_create_too_few_args.stderr
@@ -4,7 +4,6 @@ error: Undefined Behavior: calling a function with more arguments than it expect
    = note: (no span available)
    = 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`:
 
 error: aborting due to 1 previous error
 
diff --git a/tests/fail-dep/concurrency/libc_pthread_create_too_many_args.stderr b/tests/fail-dep/concurrency/libc_pthread_create_too_many_args.stderr
@@ -4,7 +4,6 @@ error: Undefined Behavior: calling a function with fewer arguments than it requi
    = note: (no span available)
    = 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`:
 
 error: aborting due to 1 previous error
 
diff --git a/tests/fail-dep/concurrency/libc_pthread_join_detached.stderr b/tests/fail-dep/concurrency/libc_pthread_join_detached.stderr
@@ -6,8 +6,6 @@ LL |         assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_join_detached.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_join_joined.stderr b/tests/fail-dep/concurrency/libc_pthread_join_joined.stderr
@@ -6,8 +6,6 @@ LL | ...   assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_join_joined.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_join_main.stderr b/tests/fail-dep/concurrency/libc_pthread_join_main.stderr
@@ -6,8 +6,6 @@ LL | ...   assert_eq!(libc::pthread_join(thread_id, ptr::null_mut()), 0);
    |
    = 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: inside closure at tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_join_multiple.stderr b/tests/fail-dep/concurrency/libc_pthread_join_multiple.stderr
@@ -6,8 +6,6 @@ LL | ...   assert_eq!(libc::pthread_join(native_copy, ptr::null_mut()), 0);
    |
    = 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: inside closure at tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_join_self.stderr b/tests/fail-dep/concurrency/libc_pthread_join_self.stderr
@@ -6,8 +6,6 @@ LL |             assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
    |
    = 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: inside closure at tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_NULL_reentrant.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_NULL_reentrant.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_NULL_reentrant.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.stderr
@@ -3,9 +3,6 @@ error: the evaluated program deadlocked
    |
 LL |             assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _), 0);
    |                                                                            ^ this thread got stuck here
-   |
-   = note: BACKTRACE on thread `unnamed-ID`:
-   = note: inside closure at tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC
 
 error: the evaluated program deadlocked
   --> RUSTLIB/std/src/sys/thread/PLATFORM.rs:LL:CC

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_default_reentrant.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_default_reentrant.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_default_reentrant.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_destroy_locked.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_destroy_locked.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutex_destroy(&mut mutex as *mut _);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_destroy_locked.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs:LL:CC
 
 Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
 ALLOC DUMP

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_normal_reentrant.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_normal_reentrant.stderr
@@ -3,9 +3,6 @@ error: the evaluated program deadlocked
    |
 LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this thread got stuck here
-   |
-   = note: BACKTRACE:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_normal_reentrant.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_normal_unlock_unlocked.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_normal_unlock_unlocked.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutex_unlock(&mut mutex as *mut _);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_normal_unlock_unlocked.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_staticinit_reentrant.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_staticinit_reentrant.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_staticinit_reentrant.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.stderr b/tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.stderr
@@ -6,8 +6,6 @@ LL | ...   assert_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0
    |
    = 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: inside closure at tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr b/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs:LL:CC
 
 Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
 ALLOC DUMP

diff --git a/tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_read_locked.stderr b/tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_read_locked.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_rwlock_destroy(rw.get());
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_read_locked.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_write_locked.stderr b/tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_write_locked.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_rwlock_destroy(rw.get());
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_write_locked.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

diff --git a/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr b/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr
@@ -6,8 +6,6 @@ LL |         libc::pthread_rwlock_destroy(&mut lock);
    |
    = 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:
-   = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs:LL:CC
 
 Uninitialized memory occurred at ALLOC[0xX..0xY], in this allocation:
 ALLOC DUMP