Index: lib/sanitizer_common/sanitizer_common.h
===================================================================
--- lib/sanitizer_common/sanitizer_common.h
+++ lib/sanitizer_common/sanitizer_common.h
@@ -378,7 +378,7 @@
 void ReportErrorSummary(const char *error_type, const StackTrace *trace,
                         const char *alt_tool_name = nullptr);
 
-void ReportMmapWriteExec();
+void ReportMmapWriteExec(int prot);
 
 // Math
 #if SANITIZER_WINDOWS && !defined(__clang__) && !defined(__GNUC__)
Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -35,6 +35,7 @@
 //   COMMON_INTERCEPTOR_MEMMOVE_IMPL
 //   COMMON_INTERCEPTOR_MEMCPY_IMPL
 //   COMMON_INTERCEPTOR_MMAP_IMPL
+//   COMMON_INTERCEPTOR_MPROTECT_IMPL
 //   COMMON_INTERCEPTOR_COPY_STRING
 //   COMMON_INTERCEPTOR_STRNDUP_IMPL
 //===----------------------------------------------------------------------===//
@@ -274,6 +275,11 @@
   { return REAL(mmap)(addr, sz, prot, flags, fd, off); }
 #endif
 
+#ifndef COMMON_INTERCEPTOR_MPROTECT_IMPL
+#define COMMON_INTERCEPTOR_MPROTECT_IMPL(ctx, mprotect, addr, sz, prot) \
+  { return REAL(mprotect)(addr, sz, prot); }
+#endif
+
 #ifndef COMMON_INTERCEPTOR_COPY_STRING
 #define COMMON_INTERCEPTOR_COPY_STRING(ctx, to, from, size) {}
 #endif
@@ -6888,13 +6894,25 @@
             OFF_T off) {
   void *ctx;
   if (common_flags()->detect_write_exec)
-    ReportMmapWriteExec();
+    ReportMmapWriteExec(prot);
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return (void *)internal_mmap(addr, sz, prot, flags, fd, off);
   COMMON_INTERCEPTOR_ENTER(ctx, mmap, addr, sz, prot, flags, fd, off);
   COMMON_INTERCEPTOR_MMAP_IMPL(ctx, mmap, addr, sz, prot, flags, fd, off);
 }
-#define INIT_MMAP COMMON_INTERCEPT_FUNCTION(mmap);
+
+INTERCEPTOR(int, mprotect, void *addr, SIZE_T sz, int prot) {
+  void *ctx;
+  if (common_flags()->detect_write_exec)
+    ReportMmapWriteExec(prot);
+  if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
+    return (int)internal_mprotect(addr, sz, prot);
+  COMMON_INTERCEPTOR_ENTER(ctx, mprotect, addr, sz, prot);
+  COMMON_INTERCEPTOR_MPROTECT_IMPL(ctx, mprotect, addr, sz, prot);
+}
+#define INIT_MMAP \
+  COMMON_INTERCEPT_FUNCTION(mmap); \
+  COMMON_INTERCEPT_FUNCTION(mprotect);
 #else
 #define INIT_MMAP
 #endif
@@ -6904,7 +6922,7 @@
             OFF64_T off) {
   void *ctx;
   if (common_flags()->detect_write_exec)
-    ReportMmapWriteExec();
+    ReportMmapWriteExec(prot);
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return (void *)internal_mmap(addr, sz, prot, flags, fd, off);
   COMMON_INTERCEPTOR_ENTER(ctx, mmap64, addr, sz, prot, flags, fd, off);
Index: lib/sanitizer_common/sanitizer_common_libcdep.cc
===================================================================
--- lib/sanitizer_common/sanitizer_common_libcdep.cc
+++ lib/sanitizer_common/sanitizer_common_libcdep.cc
@@ -24,6 +24,8 @@
 
 #if SANITIZER_POSIX
 #include "sanitizer_posix.h"
+
+#include <sys/mman.h>
 #endif
 
 namespace __sanitizer {
@@ -81,8 +83,11 @@
 #endif
 }
 
-void ReportMmapWriteExec() {
+void ReportMmapWriteExec(int prot) {
 #if !SANITIZER_GO && !SANITIZER_ANDROID
+  if ((prot & (PROT_WRITE | PROT_EXEC)) != (PROT_WRITE | PROT_EXEC))
+    return;
+
   ScopedErrorReportLock l;
   SanitizerCommonDecorator d;
 
Index: test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp
===================================================================
--- test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp
+++ test/sanitizer_common/TestCases/Linux/mmap_write_exec.cpp
@@ -12,4 +12,8 @@
   char *p = (char *)mmap(0, 1024, PROT_READ | PROT_WRITE | PROT_EXEC,
                          MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
   // CHECK: WARNING: {{.*}}Sanitizer: writable-executable page usage
+  char *q = (char *)mmap(p, 64, PROT_READ | PROT_WRITE,
+                         MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+  (void)mprotect(q, 64, PROT_WRITE | PROT_EXEC);
+  // CHECK: WARNING: {{.*}}Sanitizer: writable-executable page usage
 }