[compiler-rt] [tsan] Change personality CHECK to Printf() + Die() (PR #142821)

[Thurston Dang via llvm-commits]

https://github.com/thurstond updated https://github.com/llvm/llvm-project/pull/142821

>From 388b83e745815fe839cd329c2c7a6ea7ddd2248d Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Wed, 4 Jun 2025 17:37:09 +0000
Subject: [PATCH 1/3] [tsan] Change personality CHECK to Printf() + Die()

Currently, if TSan needs to disable ASLR but is unable to do so, it
aborts with a cryptic message:
    ThreadSanitizer: CHECK failed: tsan_platform_linux.cpp:290 "((personality(old_personality | ADDR_NO_RANDOMIZE))) != ((-1))"
and a segfault (https://github.com/google/sanitizers/issues/837#issuecomment-2939267531).

This patch replaces the CHECK with more user-friendly diagnostics and
suggestions via printf, followed by Die().
---
 .../lib/tsan/rtl/tsan_platform_linux.cpp      | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
index 373acd3d95d01..a20c83ab37159 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
@@ -259,7 +259,14 @@ static void ReExecIfNeeded(bool ignore_heap) {
             "WARNING: Program is run with randomized virtual address "
             "space, which wouldn't work with ThreadSanitizer on Android.\n"
             "Re-execing with fixed virtual address space.\n");
-    CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
+
+    if (personality(old_personality | ADDR_NO_RANDOMIZE) == -1) {
+      Printf("FATAL: ThreadSanitizer: unable to disable ASLR (perhaps "
+             "sandboxing is enabled?).\n");
+      Printf("FATAL: Please rerun without sandboxing or ASLR.\n");
+      Die();
+    }
+
     reexec = true;
   }
 #      endif
@@ -287,7 +294,16 @@ static void ReExecIfNeeded(bool ignore_heap) {
               "possibly due to high-entropy ASLR.\n"
               "Re-execing with fixed virtual address space.\n"
               "N.B. reducing ASLR entropy is preferable.\n");
-      CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
+
+      if (personality(old_personality | ADDR_NO_RANDOMIZE) == -1) {
+        Printf("FATAL: ThreadSanitizer: encountered an incompatible memory "
+               "but was unable to disable ASLR (perhaps sandboxing is "
+               "enabled?).\n");
+        Printf("FATAL: Please rerun with lower ASLR entropy, ASLR disabled, "
+               "and/or sandboxing disabled.\n");
+        Die();
+      }
+
       reexec = true;
     } else {
       Printf(

>From a601f6cec759fb22af2561ea17108d05127b6ca2 Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Wed, 4 Jun 2025 17:41:17 +0000
Subject: [PATCH 2/3] Clarify and/or

---
 compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
index a20c83ab37159..331ec6e39de89 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
@@ -263,7 +263,7 @@ static void ReExecIfNeeded(bool ignore_heap) {
     if (personality(old_personality | ADDR_NO_RANDOMIZE) == -1) {
       Printf("FATAL: ThreadSanitizer: unable to disable ASLR (perhaps "
              "sandboxing is enabled?).\n");
-      Printf("FATAL: Please rerun without sandboxing or ASLR.\n");
+      Printf("FATAL: Please rerun without sandboxing and/or ASLR.\n");
       Die();
     }
 

>From 0f4f8cd2aed692bd91e44b6de8f8f5c5336479fe Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Wed, 4 Jun 2025 17:41:33 +0000
Subject: [PATCH 3/3] clang-format

---
 .../lib/tsan/rtl/tsan_platform_linux.cpp        | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
index 331ec6e39de89..469525ac41cf8 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
@@ -261,8 +261,9 @@ static void ReExecIfNeeded(bool ignore_heap) {
             "Re-execing with fixed virtual address space.\n");
 
     if (personality(old_personality | ADDR_NO_RANDOMIZE) == -1) {
-      Printf("FATAL: ThreadSanitizer: unable to disable ASLR (perhaps "
-             "sandboxing is enabled?).\n");
+      Printf(
+          "FATAL: ThreadSanitizer: unable to disable ASLR (perhaps "
+          "sandboxing is enabled?).\n");
       Printf("FATAL: Please rerun without sandboxing and/or ASLR.\n");
       Die();
     }
@@ -296,11 +297,13 @@ static void ReExecIfNeeded(bool ignore_heap) {
               "N.B. reducing ASLR entropy is preferable.\n");
 
       if (personality(old_personality | ADDR_NO_RANDOMIZE) == -1) {
-        Printf("FATAL: ThreadSanitizer: encountered an incompatible memory "
-               "but was unable to disable ASLR (perhaps sandboxing is "
-               "enabled?).\n");
-        Printf("FATAL: Please rerun with lower ASLR entropy, ASLR disabled, "
-               "and/or sandboxing disabled.\n");
+        Printf(
+            "FATAL: ThreadSanitizer: encountered an incompatible memory "
+            "but was unable to disable ASLR (perhaps sandboxing is "
+            "enabled?).\n");
+        Printf(
+            "FATAL: Please rerun with lower ASLR entropy, ASLR disabled, "
+            "and/or sandboxing disabled.\n");
         Die();
       }