diff --git a/src/tools/miri/src/borrow_tracker/mod.rs b/src/tools/miri/src/borrow_tracker/mod.rs
index fcfa8f64570..b6dfd9944ee 100644
--- a/src/tools/miri/src/borrow_tracker/mod.rs
+++ b/src/tools/miri/src/borrow_tracker/mod.rs
@@ -413,7 +413,7 @@ pub fn before_memory_write<'tcx>(
         alloc_id: AllocId,
         prov_extra: ProvenanceExtra,
         range: AllocRange,
-        machine: &mut MiriMachine<'_, 'tcx>,
+        machine: &MiriMachine<'_, 'tcx>,
     ) -> InterpResult<'tcx> {
         match self {
             AllocState::StackedBorrows(sb) =>
@@ -434,7 +434,7 @@ pub fn before_memory_deallocation<'tcx>(
         alloc_id: AllocId,
         prov_extra: ProvenanceExtra,
         range: AllocRange,
-        machine: &mut MiriMachine<'_, 'tcx>,
+        machine: &MiriMachine<'_, 'tcx>,
     ) -> InterpResult<'tcx> {
         match self {
             AllocState::StackedBorrows(sb) =>
diff --git a/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs b/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
index 15a7d72edf1..7e89d3a0e8c 100644
--- a/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
+++ b/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
@@ -244,7 +244,7 @@ fn find_first_write_incompatible(&self, granting: usize) -> usize {
     fn item_invalidated(
         item: &Item,
         global: &GlobalStateInner,
-        dcx: &mut DiagnosticCx<'_, '_, '_, 'tcx>,
+        dcx: &DiagnosticCx<'_, '_, '_, 'tcx>,
         cause: ItemInvalidationCause,
     ) -> InterpResult<'tcx> {
         if !global.tracked_pointer_tags.is_empty() {
@@ -575,7 +575,7 @@ pub fn before_memory_write<'tcx>(
         alloc_id: AllocId,
         tag: ProvenanceExtra,
         range: AllocRange,
-        machine: &mut MiriMachine<'_, 'tcx>,
+        machine: &MiriMachine<'_, 'tcx>,
     ) -> InterpResult<'tcx> {
         trace!(
             "write access with tag {:?}: {:?}, size {}",
@@ -596,7 +596,7 @@ pub fn before_memory_deallocation<'tcx>(
         alloc_id: AllocId,
         tag: ProvenanceExtra,
         range: AllocRange,
-        machine: &mut MiriMachine<'_, 'tcx>,
+        machine: &MiriMachine<'_, 'tcx>,
     ) -> InterpResult<'tcx> {
         trace!("deallocation with tag {:?}: {:?}, size {}", tag, alloc_id, range.size.bytes());
         let dcx = DiagnosticCxBuilder::dealloc(machine, tag);
diff --git a/src/tools/miri/src/shims/unix/sync.rs b/src/tools/miri/src/shims/unix/sync.rs
index 94b831da5c8..1fa0ffd8ee7 100644
--- a/src/tools/miri/src/shims/unix/sync.rs
+++ b/src/tools/miri/src/shims/unix/sync.rs
@@ -18,14 +18,14 @@
 const PTHREAD_MUTEX_NORMAL_FLAG: i32 = 0x8000000;
 
 fn is_mutex_kind_default<'mir, 'tcx: 'mir>(
-    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    ecx: &MiriInterpCx<'mir, 'tcx>,
     kind: i32,
 ) -> InterpResult<'tcx, bool> {
     Ok(kind == ecx.eval_libc_i32("PTHREAD_MUTEX_DEFAULT"))
 }
 
 fn is_mutex_kind_normal<'mir, 'tcx: 'mir>(
-    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    ecx: &MiriInterpCx<'mir, 'tcx>,
     kind: i32,
 ) -> InterpResult<'tcx, bool> {
     let mutex_normal_kind = ecx.eval_libc_i32("PTHREAD_MUTEX_NORMAL");