diff --git a/src/julia_internal.h b/src/julia_internal.h
index 7b40f59ae75b0..6cd1a8d8c9b19 100644
--- a/src/julia_internal.h
+++ b/src/julia_internal.h
@@ -1163,8 +1163,8 @@ JL_DLLEXPORT jl_value_t *jl_get_backtrace(void);
 void jl_critical_error(int sig, int si_code, bt_context_t *context, jl_task_t *ct);
 JL_DLLEXPORT void jl_raise_debugger(void) JL_NOTSAFEPOINT;
 JL_DLLEXPORT void jl_gdblookup(void* ip) JL_NOTSAFEPOINT;
-void jl_print_native_codeloc(uintptr_t ip) JL_NOTSAFEPOINT;
-void jl_print_bt_entry_codeloc(jl_bt_element_t *bt_data) JL_NOTSAFEPOINT;
+void jl_print_native_codeloc(char *pre_str, uintptr_t ip) JL_NOTSAFEPOINT;
+void jl_print_bt_entry_codeloc(int sig, jl_bt_element_t *bt_data) JL_NOTSAFEPOINT;
 #ifdef _OS_WINDOWS_
 JL_DLLEXPORT void jl_refresh_dbg_module_list(void);
 #endif
diff --git a/src/signal-handling.c b/src/signal-handling.c
index e241fd22ecb18..b280fc1e0aeef 100644
--- a/src/signal-handling.c
+++ b/src/signal-handling.c
@@ -475,7 +475,7 @@ void jl_critical_error(int sig, int si_code, bt_context_t *context, jl_task_t *c
         *bt_size = n = rec_backtrace_ctx(bt_data, JL_MAX_BT_SIZE, context, NULL);
     }
     for (i = 0; i < n; i += jl_bt_entry_size(bt_data + i)) {
-        jl_print_bt_entry_codeloc(bt_data + i);
+        jl_print_bt_entry_codeloc(sig, bt_data + i);
     }
     jl_gc_debug_print_status();
     jl_gc_debug_critical_error();
diff --git a/src/signals-unix.c b/src/signals-unix.c
index 0d5ad9b1be7c5..a79043d78e682 100644
--- a/src/signals-unix.c
+++ b/src/signals-unix.c
@@ -956,7 +956,7 @@ static void *signal_listener(void *arg)
             jl_safe_printf("\nsignal (%d): %s\n", sig, strsignal(sig));
             size_t i;
             for (i = 0; i < bt_size; i += jl_bt_entry_size(bt_data + i)) {
-                jl_print_bt_entry_codeloc(bt_data + i);
+                jl_print_bt_entry_codeloc(-1, bt_data + i);
             }
         }
     }
diff --git a/src/signals-win.c b/src/signals-win.c
index 10bd0dec7f480..cbf3c7436c8ff 100644
--- a/src/signals-win.c
+++ b/src/signals-win.c
@@ -327,7 +327,7 @@ LONG WINAPI jl_exception_handler(struct _EXCEPTION_POINTERS *ExceptionInfo)
         jl_safe_printf("UNKNOWN"); break;
     }
     jl_safe_printf(" at 0x%Ix -- ", (size_t)ExceptionInfo->ExceptionRecord->ExceptionAddress);
-    jl_print_native_codeloc((uintptr_t)ExceptionInfo->ExceptionRecord->ExceptionAddress);
+    jl_print_native_codeloc("", (uintptr_t)ExceptionInfo->ExceptionRecord->ExceptionAddress);
 
     jl_critical_error(0, 0, ExceptionInfo->ContextRecord, ct);
     static int recursion = 0;
diff --git a/src/stackwalk.c b/src/stackwalk.c
index dcac2c4501682..bb15ebe754533 100644
--- a/src/stackwalk.c
+++ b/src/stackwalk.c
@@ -614,22 +614,25 @@ JL_DLLEXPORT jl_value_t *jl_lookup_code_address(void *ip, int skipC)
     return rs;
 }
 
-static void jl_safe_print_codeloc(const char* func_name, const char* file_name,
+static void jl_safe_print_codeloc(const char *pre_str,
+                                  const char* func_name, const char* file_name,
                                   int line, int inlined) JL_NOTSAFEPOINT
 {
     const char *inlined_str = inlined ? " [inlined]" : "";
     if (line != -1) {
-        jl_safe_printf("%s at %s:%d%s\n", func_name, file_name, line, inlined_str);
+        jl_safe_printf("%s%s at %s:%d%s\n",
+                       pre_str, func_name, file_name, line, inlined_str);
     }
     else {
-        jl_safe_printf("%s at %s (unknown line)%s\n", func_name, file_name, inlined_str);
+        jl_safe_printf("%s%s at %s (unknown line)%s\n",
+                       pre_str, func_name, file_name, inlined_str);
     }
 }
 
 // Print function, file and line containing native instruction pointer `ip` by
 // looking up debug info. Prints multiple such frames when `ip` points to
 // inlined code.
-void jl_print_native_codeloc(uintptr_t ip) JL_NOTSAFEPOINT
+void jl_print_native_codeloc(char *pre_str, uintptr_t ip) JL_NOTSAFEPOINT
 {
     // This function is not allowed to reference any TLS variables since
     // it can be called from an unmanaged thread on OSX.
@@ -641,10 +644,11 @@ void jl_print_native_codeloc(uintptr_t ip) JL_NOTSAFEPOINT
     for (i = 0; i < n; i++) {
         jl_frame_t frame = frames[i];
         if (!frame.func_name) {
-            jl_safe_printf("unknown function (ip: %p)\n", (void*)ip);
+            jl_safe_printf("%sunknown function (ip: %p)\n", pre_str, (void*)ip);
         }
         else {
-            jl_safe_print_codeloc(frame.func_name, frame.file_name, frame.line, frame.inlined);
+            jl_safe_print_codeloc(pre_str, frame.func_name,
+                                  frame.file_name, frame.line, frame.inlined);
             free(frame.func_name);
             free(frame.file_name);
         }
@@ -653,10 +657,17 @@ void jl_print_native_codeloc(uintptr_t ip) JL_NOTSAFEPOINT
 }
 
 // Print code location for backtrace buffer entry at *bt_entry
-void jl_print_bt_entry_codeloc(jl_bt_element_t *bt_entry) JL_NOTSAFEPOINT
+void jl_print_bt_entry_codeloc(int sig, jl_bt_element_t *bt_entry) JL_NOTSAFEPOINT
 {
+    char sig_str[32], pre_str[64];
+    sig_str[0] = '\0';
+    if (sig != -1) {
+        snprintf(sig_str, 32, "signal (%d) ", sig);
+    }
+    snprintf(pre_str, 64, "%sthread (%d) ", sig_str, jl_threadid() + 1);
+
     if (jl_bt_is_native(bt_entry)) {
-        jl_print_native_codeloc(bt_entry[0].uintptr);
+        jl_print_native_codeloc(pre_str, bt_entry[0].uintptr);
     }
     else if (jl_bt_entry_tag(bt_entry) == JL_BT_INTERP_FRAME_TAG) {
         size_t ip = jl_bt_entry_header(bt_entry);
@@ -682,7 +693,7 @@ void jl_print_bt_entry_codeloc(jl_bt_element_t *bt_entry) JL_NOTSAFEPOINT
                     method = (jl_value_t*)((jl_method_t*)method)->name;
                 if (jl_is_symbol(method))
                     func_name = jl_symbol_name((jl_sym_t*)method);
-                jl_safe_print_codeloc(func_name, jl_symbol_name(locinfo->file),
+                jl_safe_print_codeloc(pre_str, func_name, jl_symbol_name(locinfo->file),
                                       locinfo->line, locinfo->inlined_at);
                 debuginfoloc = locinfo->inlined_at;
             }
@@ -1108,7 +1119,9 @@ static void jl_rec_backtrace(jl_task_t *t) JL_NOTSAFEPOINT
 
 JL_DLLEXPORT void jl_gdblookup(void* ip)
 {
-    jl_print_native_codeloc((uintptr_t)ip);
+    char pre_str[64];
+    snprintf(pre_str, 64, "thread (%d) ", jl_threadid() + 1);
+    jl_print_native_codeloc(pre_str, (uintptr_t)ip);
 }
 
 // Print backtrace for current exception in catch block
@@ -1123,7 +1136,7 @@ JL_DLLEXPORT void jlbacktrace(void) JL_NOTSAFEPOINT
     size_t i, bt_size = jl_excstack_bt_size(s, s->top);
     jl_bt_element_t *bt_data = jl_excstack_bt_data(s, s->top);
     for (i = 0; i < bt_size; i += jl_bt_entry_size(bt_data + i)) {
-        jl_print_bt_entry_codeloc(bt_data + i);
+        jl_print_bt_entry_codeloc(-1, bt_data + i);
     }
 }
 
@@ -1136,7 +1149,7 @@ JL_DLLEXPORT void jlbacktracet(jl_task_t *t) JL_NOTSAFEPOINT
     size_t i, bt_size = ptls->bt_size;
     jl_bt_element_t *bt_data = ptls->bt_data;
     for (i = 0; i < bt_size; i += jl_bt_entry_size(bt_data + i)) {
-        jl_print_bt_entry_codeloc(bt_data + i);
+        jl_print_bt_entry_codeloc(-1, bt_data + i);
     }
 }