From ef65c92144d30f04f560902fabbcfa8387d84163 Mon Sep 17 00:00:00 2001 From: Matt Jolly Date: Thu, 26 Mar 2026 15:32:06 +1000 Subject: [PATCH] [sandbox] Fix link failure with CFI builds due to missing sanitizer runtime The V8_USE_ANY_SANITIZER macro, introduced in cd1ff840fbf, includes V8_USE_UNDEFINED_BEHAVIOR_SANITIZER in its condition. This causes __sanitizer_set_death_callback (from the sanitizer common interface) to be referenced whenever any UBSan-family check is active. CFI is implemented as a UBSan check in Clang, so __has_feature(undefined_behavior_sanitizer) returns true when CFI is enabled. However, Chromium's CFI builds use trapping mode by default (-fsanitize-trap=cfi), which does NOT link the sanitizer runtime. This results in an undefined symbol error for __sanitizer_set_death_callback at link time. This was previously masked by 3138277894 ("Move sanitizer defines into GN"), which tied V8_USE_UNDEFINED_BEHAVIOR_SANITIZER to GN's is_ubsan flag rather than __has_feature detection. That commit was reverted in d3f0ec122bd, restoring the __has_feature-based detection in macros.h and re-exposing this issue. Only define V8_USE_ANY_SANITIZER when ASan or MSan is present, as these sanitizers unconditionally link the runtime that provides __sanitizer_set_death_callback. UBSan alone cannot be relied upon since there is no preprocessor way to distinguish trapping mode (no runtime) from diagnostic mode (has runtime). Bug: 430178746 Signed-off-by: Matt Jolly --- a/v8/src/sandbox/testing.cc +++ b/v8/src/sandbox/testing.cc @@ -37,8 +37,17 @@ #include #endif -#if defined(V8_USE_ADDRESS_SANITIZER) || defined(V8_USE_MEMORY_SANITIZER) || \ - defined(V8_USE_UNDEFINED_BEHAVIOR_SANITIZER) +// Note: CFI is implemented as a UBSan check in Clang, so +// __has_feature(undefined_behavior_sanitizer) is true when CFI is enabled and +// V8_USE_UNDEFINED_BEHAVIOR_SANITIZER will be defined. However, CFI in trapping +// mode (Chromium's default) does NOT link the sanitizer runtime, so symbols +// like __sanitizer_set_death_callback are unavailable. Only ASan and MSan +// unconditionally link the sanitizer runtime that provides the common interface. +// UBSan only links its runtime in non-trapping (diagnostic) mode, and there is +// no reliable preprocessor check to distinguish trapping vs non-trapping UBSan. +// Therefore, only define V8_USE_ANY_SANITIZER when ASan or MSan is present, +// which guarantees the common sanitizer runtime is linked. +#if defined(V8_USE_ADDRESS_SANITIZER) || defined(V8_USE_MEMORY_SANITIZER) #define V8_USE_ANY_SANITIZER 1 #include #endif -- 2.52.0