[scudo] Skip AllocAfterFork test on machines with low max_map_count
Reducing the number of iterations in that test with D111342 helped,
but the failure still occured flakily when the test is ran as part
of a large test suite.
Reducing further the number of iterations might not be good enough,
so we will skip the test if the `max_map_count` variable can be
read, and if lower than a given threshold.
Differential Revision: https://reviews.llvm.org/D111465
GitOrigin-RevId: 56a9effc427b10203dfb7f691a12924a82ba5cd5
diff --git a/tests/wrappers_cpp_test.cpp b/tests/wrappers_cpp_test.cpp
index 5099e6d..a88dc4a 100644
--- a/tests/wrappers_cpp_test.cpp
+++ b/tests/wrappers_cpp_test.cpp
@@ -11,6 +11,7 @@
#include <atomic>
#include <condition_variable>
+#include <fstream>
#include <memory>
#include <mutex>
#include <thread>
@@ -131,6 +132,22 @@
#if !SCUDO_FUCHSIA
TEST(ScudoWrappersCppTest, AllocAfterFork) {
+ // This test can fail flakily when ran as a part of large number of
+ // other tests if the maxmimum number of mappings allowed is low.
+ // We tried to reduce the number of iterations of the loops with
+ // moderate success, so we will now skip this test under those
+ // circumstances.
+ if (SCUDO_LINUX) {
+ long MaxMapCount = 0;
+ // If the file can't be accessed, we proceed with the test.
+ std::ifstream Stream("/proc/sys/vm/max_map_count");
+ if (Stream.good()) {
+ Stream >> MaxMapCount;
+ if (MaxMapCount < 200000)
+ return;
+ }
+ }
+
std::atomic_bool Stop;
// Create threads that simply allocate and free different sizes.
