Index: include/sanitizer/common_interface_defs.h
===================================================================
--- include/sanitizer/common_interface_defs.h
+++ include/sanitizer/common_interface_defs.h
@@ -85,6 +85,9 @@
                                                  const void *old_mid,
                                                  const void *new_mid);
 
+  // Print the stack trace leading to this call. Useful for debugging user code.
+  void __sanitizer_print_stack_trace();
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif
Index: lib/asan/asan_stack.cc
===================================================================
--- lib/asan/asan_stack.cc
+++ lib/asan/asan_stack.cc
@@ -45,3 +45,11 @@
   return false;
 }
 #endif
+
+using namespace __asan;  // NOLINT
+
+SANITIZER_INTERFACE_ATTRIBUTE
+extern "C" void __sanitizer_print_stack_trace() {
+  GET_STACK_TRACE_FATAL_HERE;
+  PrintStack(&stack);
+}
Index: lib/lsan/lsan.h
===================================================================
--- lib/lsan/lsan.h
+++ lib/lsan/lsan.h
@@ -14,6 +14,20 @@
 
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_stacktrace.h"
+#include "lsan_thread.h"
+
+#define GET_STACK_TRACE(max_size, fast)                                      \
+  StackTrace stack;                                                          \
+  {                                                                          \
+    uptr stack_top = 0, stack_bottom = 0;                                    \
+    ThreadContext *t;                                                        \
+    if (fast && (t = CurrentThreadContext())) {                              \
+      stack_top = t->stack_end();                                            \
+      stack_bottom = t->stack_begin();                                       \
+    }                                                                        \
+    stack.Unwind(max_size, StackTrace::GetCurrentPc(),                       \
+                 GET_CURRENT_FRAME(), stack_top, stack_bottom, fast);        \
+  }
 
 namespace __lsan {
 
Index: lib/lsan/lsan.cc
===================================================================
--- lib/lsan/lsan.cc
+++ lib/lsan/lsan.cc
@@ -69,3 +69,10 @@
   lsan_init_is_running = false;
 }
 
+// ------------------ Interface -------------- {{{1
+
+SANITIZER_INTERFACE_ATTRIBUTE
+extern "C" void __sanitizer_print_stack_trace() {
+  GET_STACK_TRACE(kStackTraceMax, common_flags()->fast_unwind_on_fatal)
+  StackTrace::PrintStack(stack.trace, stack.size);
+}
Index: lib/lsan/lsan_common.cc
===================================================================
--- lib/lsan/lsan_common.cc
+++ lib/lsan/lsan_common.cc
@@ -535,6 +535,8 @@
 }  // namespace __lsan
 #endif  // CAN_SANITIZE_LEAKS
 
+// ------------------ Interface -------------- {{{1
+
 using namespace __lsan;  // NOLINT
 
 extern "C" {
Index: lib/lsan/lsan_interceptors.cc
===================================================================
--- lib/lsan/lsan_interceptors.cc
+++ lib/lsan/lsan_interceptors.cc
@@ -34,20 +34,9 @@
 int pthread_setspecific(unsigned key, const void *v);
 }
 
-#define GET_STACK_TRACE                                                      \
-  StackTrace stack;                                                          \
-  {                                                                          \
-    uptr stack_top = 0, stack_bottom = 0;                                    \
-    ThreadContext *t;                                                        \
-    bool fast = common_flags()->fast_unwind_on_malloc;                       \
-    if (fast && (t = CurrentThreadContext())) {                              \
-      stack_top = t->stack_end();                                            \
-      stack_bottom = t->stack_begin();                                       \
-    }                                                                        \
-    stack.Unwind(__sanitizer::common_flags()->malloc_context_size,           \
-                 StackTrace::GetCurrentPc(),                                 \
-                 GET_CURRENT_FRAME(), stack_top, stack_bottom, fast);        \
-  }
+#define GET_STACK_TRACE_MALLOC                                    \
+  GET_STACK_TRACE(common_flags()->malloc_context_size,            \
+                  common_flags()->fast_unwind_on_malloc)
 
 #define ENSURE_LSAN_INITED do {   \
   CHECK(!lsan_init_is_running);   \
@@ -65,7 +54,7 @@
 
 INTERCEPTOR(void*, malloc, uptr size) {
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   return Allocate(stack, size, 1, kAlwaysClearMemory);
 }
 
@@ -88,26 +77,26 @@
   }
   if (CallocShouldReturnNullDueToOverflow(size, nmemb)) return 0;
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   size *= nmemb;
   return Allocate(stack, size, 1, true);
 }
 
 INTERCEPTOR(void*, realloc, void *q, uptr size) {
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   return Reallocate(stack, q, size, 1);
 }
 
 INTERCEPTOR(void*, memalign, uptr alignment, uptr size) {
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   return Allocate(stack, size, alignment, kAlwaysClearMemory);
 }
 
 INTERCEPTOR(int, posix_memalign, void **memptr, uptr alignment, uptr size) {
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   *memptr = Allocate(stack, size, alignment, kAlwaysClearMemory);
   // FIXME: Return ENOMEM if user requested more than max alloc size.
   return 0;
@@ -115,7 +104,7 @@
 
 INTERCEPTOR(void*, valloc, uptr size) {
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   if (size == 0)
     size = GetPageSizeCached();
   return Allocate(stack, size, GetPageSizeCached(), kAlwaysClearMemory);
@@ -142,7 +131,7 @@
 
 INTERCEPTOR(void*, pvalloc, uptr size) {
   ENSURE_LSAN_INITED;
-  GET_STACK_TRACE;
+  GET_STACK_TRACE_MALLOC;
   uptr PageSize = GetPageSizeCached();
   size = RoundUpTo(size, PageSize);
   if (size == 0) {
@@ -156,7 +145,7 @@
 
 #define OPERATOR_NEW_BODY                              \
   ENSURE_LSAN_INITED;                                  \
-  GET_STACK_TRACE;                                     \
+  GET_STACK_TRACE_MALLOC;                              \
   return Allocate(stack, size, 1, kAlwaysClearMemory);
 
 INTERCEPTOR_ATTRIBUTE
Index: lib/msan/msan.cc
===================================================================
--- lib/msan/msan.cc
+++ lib/msan/msan.cc
@@ -192,6 +192,12 @@
   stack->Unwind(max_s, pc, bp, stack_top, stack_bottom, request_fast_unwind);
 }
 
+// Inlining confuses the slow unwinder in __sanitizer_print_stack_trace().
+NOINLINE void GetStackTraceNoInline(StackTrace *stack, uptr max_s, uptr pc,
+                                    uptr bp, bool request_fast_unwind) {
+  GetStackTrace(stack, max_s, pc, bp, request_fast_unwind);
+}
+
 void PrintWarning(uptr pc, uptr bp) {
   PrintWarningWithOrigin(pc, bp, __msan_origin_tls);
 }
@@ -570,3 +576,14 @@
 }  // extern "C"
 #endif
 
+SANITIZER_INTERFACE_ATTRIBUTE
+extern "C" void __sanitizer_print_stack_trace() {
+  StackTrace stack;
+  stack.size = 0;
+  if (msan_inited)
+    GetStackTraceNoInline(&stack, kStackTraceMax, StackTrace::GetCurrentPc(),
+                          GET_CURRENT_FRAME(),
+                          common_flags()->fast_unwind_on_fatal);
+  StackTrace::PrintStack(stack.trace, stack.size);
+}
+
Index: lib/tsan/rtl/tsan_interface.cc
===================================================================
--- lib/tsan/rtl/tsan_interface.cc
+++ lib/tsan/rtl/tsan_interface.cc
@@ -87,6 +87,11 @@
 SANITIZER_INTERFACE_ATTRIBUTE
 void __sanitizer_unaligned_store64(void *addr, uint64_t v)
     ALIAS("__tsan_unaligned_write8");
+
+void __sanitizer_print_stack_trace() {
+  ScopedInRtl in_rtl;
+  PrintCurrentStackSlow();
+}
 }
 
 void __tsan_acquire(void *addr) {