[compiler-rt] [tsan] Intercept __tls_get_addr_earlier (PR #83886)

[Alexander Richardson via llvm-commits]

https://github.com/arichardson updated https://github.com/llvm/llvm-project/pull/83886

>From 289f4be8b0f58bb61dab37703d9834a3c3d20cbf Mon Sep 17 00:00:00 2001
From: Alex Richardson <alexrichardson at google.com>
Date: Mon, 4 Mar 2024 10:32:30 -0800
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.6-beta.1
---
 .../lib/tsan/rtl/tsan_interceptors_posix.cpp  | 23 +++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
index a9f6673ac44e90..b8bfaf500c2769 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -2863,6 +2863,20 @@ void InitializeInterceptors() {
 
   new(interceptor_ctx()) InterceptorContext();
 
+  // Interpose __tls_get_addr before the common interposers. This is needed
+  // because dlsym() may call malloc on failure. And then ___interceptor_malloc
+  // can end up calling ___interceptor___tls_get_addr, which would not be
+  // initialized yet and therefore results in a crash when calling
+  // REAL(__tls_get_addr). For example, this can happen when looking up
+  // __isoc23_scanf which might not exist in some libcs.
+#ifdef NEED_TLS_GET_ADDR
+#  if !SANITIZER_S390
+  TSAN_INTERCEPT(__tls_get_addr);
+#  else
+  TSAN_INTERCEPT(__tls_get_addr_internal);
+  TSAN_INTERCEPT(__tls_get_offset);
+#  endif
+#endif
   InitializeCommonInterceptors();
   InitializeSignalInterceptors();
   InitializeLibdispatchInterceptors();
@@ -3010,15 +3024,6 @@ void InitializeInterceptors() {
   TSAN_INTERCEPT(__cxa_atexit);
   TSAN_INTERCEPT(_exit);
 
-#ifdef NEED_TLS_GET_ADDR
-#if !SANITIZER_S390
-  TSAN_INTERCEPT(__tls_get_addr);
-#else
-  TSAN_INTERCEPT(__tls_get_addr_internal);
-  TSAN_INTERCEPT(__tls_get_offset);
-#endif
-#endif
-
   TSAN_MAYBE_INTERCEPT__LWP_EXIT;
   TSAN_MAYBE_INTERCEPT_THR_EXIT;