[scudo] Remove ResidentMemorySize test.

[cferris1000]

This test is not very accurate, and nearly everything in Scudo would fail if this didn't work. It's now failing in Android, which is the reason for deleting.

Filed bug to replace with a more accurate version of this test.

[llvmbot]

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

Author: Christopher Ferris (cferris1000)

Changes

This test is not very accurate, and nearly everything in Scudo would fail if this didn't work. It's now failing in Android, which is the reason for deleting.

Filed bug to replace with a more accurate version of this test.

---

Full diff: https://github.com/llvm/llvm-project/pull/145955.diff

1 Files Affected:

• (modified) compiler-rt/lib/scudo/standalone/tests/common_test.cpp (-37)

diff --git a/compiler-rt/lib/scudo/standalone/tests/common_test.cpp b/compiler-rt/lib/scudo/standalone/tests/common_test.cpp
index e6ddbb00b843c..b63706694c3ac 100644
--- a/compiler-rt/lib/scudo/standalone/tests/common_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/common_test.cpp
@@ -16,43 +16,6 @@
 
 namespace scudo {
 
-static uptr getResidentMemorySize() {
-  if (!SCUDO_LINUX)
-    UNREACHABLE("Not implemented!");
-  uptr Size;
-  uptr Resident;
-  std::ifstream IFS("/proc/self/statm");
-  IFS >> Size;
-  IFS >> Resident;
-  return Resident * getPageSizeCached();
-}
-
-// Fuchsia needs getResidentMemorySize implementation.
-TEST(ScudoCommonTest, SKIP_ON_FUCHSIA(ResidentMemorySize)) {
-  uptr OnStart = getResidentMemorySize();
-  EXPECT_GT(OnStart, 0UL);
-
-  const uptr Size = 1ull << 30;
-  const uptr Threshold = Size >> 3;
-
-  MemMapT MemMap;
-  ASSERT_TRUE(MemMap.map(/*Addr=*/0U, Size, "ResidentMemorySize"));
-  ASSERT_NE(MemMap.getBase(), 0U);
-  void *P = reinterpret_cast<void *>(MemMap.getBase());
-  EXPECT_LT(getResidentMemorySize(), OnStart + Threshold);
-
-  memset(P, 1, Size);
-  EXPECT_GT(getResidentMemorySize(), OnStart + Size - Threshold);
-
-  MemMap.releasePagesToOS(MemMap.getBase(), Size);
-  EXPECT_LT(getResidentMemorySize(), OnStart + Threshold);
-
-  memset(P, 1, Size);
-  EXPECT_GT(getResidentMemorySize(), OnStart + Size - Threshold);
-
-  MemMap.unmap();
-}
-
 TEST(ScudoCommonTest, Zeros) {
   const uptr Size = 1ull << 20;
 

[vitalybuka]

This is the only test which detect change like this, and we have qemu bug was broken in exactly like this. So I believe it's still useful.

--- a/compiler-rt/lib/scudo/standalone/mem_map_linux.cpp
+++ b/compiler-rt/lib/scudo/standalone/mem_map_linux.cpp
@@ -122,8 +122,9 @@ void MemMapLinux::setMemoryPermissionImpl(uptr Addr, uptr Size, uptr Flags) {
 void MemMapLinux::releaseAndZeroPagesToOSImpl(uptr From, uptr Size) {
   void *Addr = reinterpret_cast<void *>(From);
 
-  while (madvise(Addr, Size, MADV_DONTNEED) == -1 && errno == EAGAIN) {
-  }
+  memset((void*)(Addr), 0, Size);
+  // while (madvise(Addr, Size, MADV_DONTNEED) == -1 && errno == EAGAIN) {
+  // }
 }
 
 bool ReservedMemoryLinux::createImpl(uptr Addr, uptr Size, const char *Name,