[msan] Change personality CHECK to Printf() + Die()

[thurstond]

This ports #142821 from TSan.

Although MSan doesn't segfault the way TSan did, the failure message was nonetheless cryptic. The improved error message will prepare MSan for the upcoming AppArmorpocalypse.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Thurston Dang (thurstond)

Changes

This ports #142821 from TSan.

Although MSan doesn't segfault the way TSan did, the failure message was nonetheless cryptic. The improved error message will prepare MSan for the upcoming AppArmorpocalypse.

---

Full diff: https://github.com/llvm/llvm-project/pull/160626.diff

1 Files Affected:

• (modified) compiler-rt/lib/msan/msan_linux.cpp (+9-1)

diff --git a/compiler-rt/lib/msan/msan_linux.cpp b/compiler-rt/lib/msan/msan_linux.cpp
index 7140de7e9c543..f08a7c98a4847 100644
--- a/compiler-rt/lib/msan/msan_linux.cpp
+++ b/compiler-rt/lib/msan/msan_linux.cpp
@@ -190,7 +190,15 @@ bool InitShadowWithReExec(bool init_origins) {
               "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: MemorySanitizer: unable to disable ASLR (perhaps "
+            "sandboxing is enabled?).\n");
+        Printf("FATAL: Please rerun without sandboxing and/or ASLR.\n");
+        Die();
+      }
+
       ReExec();
     }
 #  endif