[compiler-rt] 96b7606 - [scudo] Fix EXPECT_DEATH tests

[Vitaly Buka via llvm-commits]

Author: Vitaly Buka
Date: 2021-05-20T17:08:15-07:00
New Revision: 96b760607f8e82e563dc8cac67b2d2dfb76d5d33

URL: https://github.com/llvm/llvm-project/commit/96b760607f8e82e563dc8cac67b2d2dfb76d5d33
DIFF: https://github.com/llvm/llvm-project/commit/96b760607f8e82e563dc8cac67b2d2dfb76d5d33.diff

LOG: [scudo] Fix EXPECT_DEATH tests

Put allocate/deallocate next to memory
access inside EXPECT_DEATH block.
This way we reduce probability that memory is not mapped
by unrelated code.

It's still not absolutely guaranty that mmap does not
happen so we repeat it few times to be sure.

Reviewed By: cryptoad

Differential Revision: https://reviews.llvm.org/D102886

Added: 
    

Modified: 
    compiler-rt/lib/scudo/standalone/tests/map_test.cpp
    compiler-rt/lib/scudo/standalone/tests/secondary_test.cpp

Removed: 
    


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diff  --git a/compiler-rt/lib/scudo/standalone/tests/map_test.cpp b/compiler-rt/lib/scudo/standalone/tests/map_test.cpp
index 7c40b73ff254..149a704e4ddd 100644
--- a/compiler-rt/lib/scudo/standalone/tests/map_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/map_test.cpp
@@ -31,11 +31,19 @@ TEST(ScudoMapTest, MapNoAccessUnmap) {
 
 TEST(ScudoMapTest, MapUnmap) {
   const scudo::uptr Size = 4 * scudo::getPageSizeCached();
-  void *P = scudo::map(nullptr, Size, MappingName, 0, nullptr);
-  EXPECT_NE(P, nullptr);
-  memset(P, 0xaa, Size);
-  scudo::unmap(P, Size, 0, nullptr);
-  EXPECT_DEATH(memset(P, 0xbb, Size), "");
+  EXPECT_DEATH(
+      {
+        // Repeat few time to avoid missing crash if it's mmaped by unrelated
+        // code.
+        for (int i = 0; i < 10; ++i) {
+          void *P = scudo::map(nullptr, Size, MappingName, 0, nullptr);
+          if (!P)
+            continue;
+          scudo::unmap(P, Size, 0, nullptr);
+          memset(P, 0xbb, Size);
+        }
+      },
+      "");
 }
 
 TEST(ScudoMapTest, MapWithGuardUnmap) {

diff  --git a/compiler-rt/lib/scudo/standalone/tests/secondary_test.cpp b/compiler-rt/lib/scudo/standalone/tests/secondary_test.cpp
index 9dcf52d909af..d5d15995be1b 100644
--- a/compiler-rt/lib/scudo/standalone/tests/secondary_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/secondary_test.cpp
@@ -39,9 +39,20 @@ template <typename Config> static void testSecondaryBasic(void) {
 // the test on arm32 until we can debug it further.
 #ifndef __arm__
   // If the Secondary can't cache that pointer, it will be unmapped.
-  if (!L->canCache(Size))
-    EXPECT_DEATH(memset(P, 'A', Size), "");
+  if (!L->canCache(Size)) {
+    EXPECT_DEATH(
+        {
+          // Repeat few time to avoid missing crash if it's mmaped by unrelated
+          // code.
+          for (int i = 0; i < 10; ++i) {
+            P = L->allocate(scudo::Options{}, Size);
+            L->deallocate(scudo::Options{}, P);
+            memset(P, 'A', Size);
+          }
+        },
+        "");
 #endif // __arm__
+  }
 
   const scudo::uptr Align = 1U << 16;
   P = L->allocate(scudo::Options{}, Size + Align, Align);