[scudo] Temporarily disable GetRssFromBuffer test

[Chia-hungDuan]

Summary

This is a flaky test and may not test the thing it expected to verify.
E.g., it doesn't dirty the pages so the memory usage may not be reflected
on the RSS.

[cferris]

Unfortunately, this test probably needs to be rewritten. If you want to keep this test, it would be best to fork/exec and use mmap to grab some memory, touch at least one byte in every page of the allocation, then do the GetRSS() call, then munmap the memory. That would be the best way to guarantee a stable change to the RSS that can be used to verify GetRSS is working correctly.

compiler-rt/lib/scudo/standalone/tests/common_test.cpp

TEST(ScudoCommonTest, Zeros) {
   EXPECT_EQ(std::count(P, P + N, 0), 0);
 
   releasePagesToOS((uptr)P, 0, Size, &Data);
   EXPECT_EQ(std::count(P, P + N, 0), N);
 
   unmap(P, Size, 0, &Data);
 }
 
-#if SCUDO_LINUX && !defined(__powerpc__)
-// This test fails intermediately on PPC, which is why this test is disabled
-// for now on this platform.
+#if 0
+// This test is temorarily disabled because it may not work as expected. E.g.,
+// it doesn't dirty the pages so the pages may not be commited and it may only
+// work on the single thread environment. As a result, this test is flaky and is
+// impacting many test scenarios.
 TEST(ScudoCommonTest, GetRssFromBuffer) {
   constexpr int64_t AllocSize = 10000000;
   constexpr int64_t Error = 3000000;
   constexpr size_t Runs = 10;
 
   int64_t Rss = scudo::GetRSS();
   EXPECT_GT(Rss, 0);
 
   std::vector<std::unique_ptr<char[]>> Allocs(Runs);
   for (auto &Alloc : Allocs) {
     Alloc.reset(new char[AllocSize]());
     int64_t Prev = Rss;
     Rss = scudo::GetRSS();
     EXPECT_LE(std::abs(Rss - AllocSize - Prev), Error);
   }
 }
-#endif // SCUDO_LINUX
+#endif
 
 } // namespace scudo