[compiler-rt] [rtsan] Fix issue where close test would lead to crash (PR #144017)

[Chris Apple via llvm-commits]

https://github.com/cjappl created https://github.com/llvm/llvm-project/pull/144017

fixes: #138311

See that ticket for the steps that led to the crash.

# Changes in this PR

1. Change so that we always try to close an open fd by making it use our OpenFile fixture
2. Ensure we never close the fd twice by adjusting the fixture
3. Out of an abundance of caution, split the test in two so we never double close.

>From 52e44c833fe5153415a86e469bcfb09188af2846 Mon Sep 17 00:00:00 2001
From: Chris Apple <cja-private at pm.me>
Date: Thu, 12 Jun 2025 22:51:14 -0600
Subject: [PATCH] [rtsan] Fix issue where close test would lead to crash

---
 .../tests/rtsan_test_interceptors_posix.cpp   | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
index 048da5858d665..aa4ad6477e6e1 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors_posix.cpp
@@ -449,12 +449,6 @@ TEST_F(RtsanFileTest, FcntlSetFdDiesWhenRealtime) {
   close(fd);
 }
 
-TEST(TestRtsanInterceptors, CloseDiesWhenRealtime) {
-  auto Func = []() { close(0); };
-  ExpectRealtimeDeath(Func, "close");
-  ExpectNonRealtimeSurvival(Func);
-}
-
 TEST(TestRtsanInterceptors, ChdirDiesWhenRealtime) {
   auto Func = []() { chdir("."); };
   ExpectRealtimeDeath(Func, "chdir");
@@ -606,8 +600,10 @@ class RtsanOpenedFileTest : public RtsanFileTest {
   }
 
   void TearDown() override {
-    if (file != nullptr)
+    const bool is_open = fcntl(fd, F_GETFD) != -1;
+    if (is_open && file != nullptr)
       fclose(file);
+
     RtsanFileTest::TearDown();
   }
 
@@ -620,6 +616,16 @@ class RtsanOpenedFileTest : public RtsanFileTest {
   int fd = -1;
 };
 
+TEST_F(RtsanOpenedFileTest, CloseDiesWhenRealtime) {
+  auto Func = [this]() { close(GetOpenFd()); };
+  ExpectRealtimeDeath(Func, "close");
+}
+
+TEST_F(RtsanOpenedFileTest, CloseSurvivesWhenNotRealtime) {
+  auto Func = [this]() { close(GetOpenFd()); };
+  ExpectNonRealtimeSurvival(Func);
+}
+
 #if SANITIZER_INTERCEPT_FSEEK
 TEST_F(RtsanOpenedFileTest, FgetposDieWhenRealtime) {
   auto Func = [this]() {