Index: lib/sanitizer_common/sanitizer_printf.cc
===================================================================
--- lib/sanitizer_common/sanitizer_printf.cc
+++ lib/sanitizer_common/sanitizer_printf.cc
@@ -260,7 +260,6 @@
                       "Buffer in Report is too short!\n"); \
       }
     if (append_pid) {
-      int pid = internal_getpid();
       const char *exe_name = GetProcessName();
       if (common_flags()->log_exe_name && exe_name) {
         needed_length += internal_snprintf(buffer, buffer_size,
@@ -269,7 +268,9 @@
       }
       needed_length += internal_snprintf(buffer + needed_length,
                                          buffer_size - needed_length,
-                                         "==%d==", pid);
+                                         "==%d:%d==",
+                                         internal_getpid(),
+                                         GetTid());
       CHECK_NEEDED_LENGTH
     }
     needed_length += VSNPrintf(buffer + needed_length,
@@ -300,7 +301,7 @@
   va_end(args);
 }
 
-// Like Printf, but prints the current PID before the output string.
+// Like Printf, but prints the current PID:TID before the output string.
 FORMAT(1, 2)
 void Report(const char *format, ...) {
   va_list args;
Index: test/sanitizer_common/TestCases/Linux/vreport.cc
===================================================================
--- /dev/null
+++ test/sanitizer_common/TestCases/Linux/vreport.cc
@@ -0,0 +1,23 @@
+// RUN: %clangxx -O0 %s -o %t && %env_tool_opts=verbosity=10 %run %t 2>&1 | FileCheck %s
+
+#include <pthread.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+void *thread(void *unused) {
+  printf("PID: %d\n", getpid());
+  printf("TID: %ld\n", syscall(SYS_gettid));
+  fflush(stdout);
+  return 0;
+}
+
+int main() {
+  pthread_t t;
+  pthread_create(&t, 0, thread, 0);
+  pthread_join(t, 0);
+  return 0;
+}
+// CHECK: PID: [[PID:[0-9]+]]
+// CHECK: TID: [[TID:[0-9]+]]
+// CHECK: ==[[PID]]:[[TID]]==