Run ThreadSanitizer tests without ASLR

Co-authored-by: Andrew Kesterson <andrew@aklabs.net>

CMakeLists.txt

@@ -107,6 +107,19 @@ if(AKERR_SANITIZE AND NOT CMAKE_C_COMPILER_ID MATCHES "GNU|Clang")
         "AKERR_SANITIZE requires GCC or Clang, not ${CMAKE_C_COMPILER_ID}")
 endif()
 
+if(AKERR_SANITIZE STREQUAL "thread" AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    # ThreadSanitizer reserves a fixed, very large virtual-address range. Linux
+    # ASLR can put a loader mapping inside it before the runtime starts, which
+    # makes every test fail with "unexpected memory mapping" before main().
+    # Run the instrumented tests under the normal util-linux ASLR wrapper.
+    find_program(AKERR_SETARCH_EXECUTABLE setarch)
+    if(NOT AKERR_SETARCH_EXECUTABLE)
+        message(FATAL_ERROR
+            "AKERR_SANITIZE=thread on Linux requires setarch (util-linux) to "
+            "start tests with ASLR disabled.")
+    endif()
+endif()
+
 function(akerr_instrument_for_sanitizers _target)
     if(AKERR_SANITIZE)
         target_compile_options(${_target} PRIVATE
@@ -252,7 +265,13 @@ foreach(_test IN LISTS AKERR_TESTS)
         target_link_libraries(test_${_test} PRIVATE Threads::Threads)
     endif()
     akerr_instrument_for_sanitizers(test_${_test})
-    add_test(NAME ${_test} COMMAND test_${_test})
+    if(AKERR_SANITIZE STREQUAL "thread" AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
+        add_test(NAME ${_test}
+                 COMMAND ${AKERR_SETARCH_EXECUTABLE} ${CMAKE_SYSTEM_PROCESSOR}
+                         -R $<TARGET_FILE:test_${_test}>)
+    else()
+        add_test(NAME ${_test} COMMAND test_${_test})
+    endif()
     # A sanitizer report is a test failure. Without halt_on_error the runtime
     # prints and continues, which leaves a race to be noticed in the log by
     # somebody reading it -- and under a race storm the reporting itself is slow