diff --git a/SConstruct b/SConstruct
index 5209aa6..79522e4 100755
--- a/SConstruct
+++ b/SConstruct
@@ -783,6 +783,10 @@
     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 
+# Valgrind gets much less confused if you tell it when you're using
+# alternative stacks.
+main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
+
 # If we have the compiler but not the library, print another warning.
 if main['PROTOC'] and not main['HAVE_PROTOBUF']:
     print(termcap.Yellow + termcap.Bold +
@@ -1012,8 +1016,8 @@
 # These variables get exported to #defines in config/*.hh (see src/SConscript).
 export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'TARGET_GPU_ISA',
                 'CP_ANNOTATE', 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP',
-                'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_PERF_ATTR_EXCLUDE_HOST',
-                'USE_PNG']
+                'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
+                'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG']
 
 ###################################################
 #
diff --git a/src/base/fiber.cc b/src/base/fiber.cc
index f10f1fb..eac1d93 100644
--- a/src/base/fiber.cc
+++ b/src/base/fiber.cc
@@ -29,6 +29,10 @@
 
 #include "base/fiber.hh"
 
+#if HAVE_VALGRIND
+#include <valgrind/valgrind.h>
+#endif
+
 #include <cerrno>
 #include <cstring>
 
@@ -71,7 +75,11 @@
     link(primaryFiber()),
     stack(stack_size ? new uint8_t[stack_size] : nullptr),
     stackSize(stack_size), started(false), _finished(false)
-{}
+{
+#if HAVE_VALGRIND
+    valgrindStackId = VALGRIND_STACK_REGISTER(stack, stack + stack_size);
+#endif
+}
 
 Fiber::Fiber(Fiber *link, size_t stack_size) :
     link(link), stack(stack_size ? new uint8_t[stack_size] : nullptr),
@@ -81,6 +89,9 @@
 Fiber::~Fiber()
 {
     panic_if(stack && _currentFiber == this, "Fiber stack is in use.");
+#if HAVE_VALGRIND
+    VALGRIND_STACK_DEREGISTER(valgrindStackId);
+#endif
     delete [] stack;
 }
 
diff --git a/src/base/fiber.hh b/src/base/fiber.hh
index 5f7285b..3d82075 100644
--- a/src/base/fiber.hh
+++ b/src/base/fiber.hh
@@ -44,6 +44,8 @@
 #include <cstddef>
 #include <cstdint>
 
+#include "config/have_valgrind.hh"
+
 /**
  * This class represents a fiber, which is a light weight sort of thread which
  * is cooperatively scheduled and runs sequentially with other fibers, swapping
@@ -106,6 +108,9 @@
     // The stack for this context, or a nullptr if allocated elsewhere.
     uint8_t *stack;
     size_t stackSize;
+#if HAVE_VALGRIND
+    unsigned valgrindStackId;
+#endif
 
     bool started;
     bool _finished;