[libc][test] fix memory leak

[nickdesaulniers]

Looks like the smart pointer I removed was being used to free the underlying
object.

Fixes: #122369

[llvmbot]

@llvm/pr-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

Changes

Looks like the smart pointer I removed was being used to free the underlying
object.

Fixes: #122369

---

Full diff: https://github.com/llvm/llvm-project/pull/122378.diff

2 Files Affected:

• (modified) libc/test/UnitTest/ExecuteFunctionUnix.cpp (+15-4)
• (modified) libc/test/UnitTest/FPExceptMatcher.cpp (+1)

diff --git a/libc/test/UnitTest/ExecuteFunctionUnix.cpp b/libc/test/UnitTest/ExecuteFunctionUnix.cpp
index df71738668592a..b004e8c0891171 100644
--- a/libc/test/UnitTest/ExecuteFunctionUnix.cpp
+++ b/libc/test/UnitTest/ExecuteFunctionUnix.cpp
@@ -36,18 +36,23 @@ int ProcessStatus::get_fatal_signal() {
 
 ProcessStatus invoke_in_subprocess(FunctionCaller *func, unsigned timeout_ms) {
   int pipe_fds[2];
-  if (::pipe(pipe_fds) == -1)
+  if (::pipe(pipe_fds) == -1) {
+    ::free(func);
     return ProcessStatus::error("pipe(2) failed");
+  }
 
   // Don't copy the buffers into the child process and print twice.
   ::fflush(stderr);
   ::fflush(stdout);
   pid_t pid = ::fork();
-  if (pid == -1)
+  if (pid == -1) {
+    ::free(func);
     return ProcessStatus::error("fork(2) failed");
+  }
 
   if (!pid) {
     (*func)();
+    ::free(func);
     ::exit(0);
   }
   ::close(pipe_fds[1]);
@@ -57,11 +62,14 @@ ProcessStatus invoke_in_subprocess(FunctionCaller *func, unsigned timeout_ms) {
   };
   // No events requested so this call will only return after the timeout or if
   // the pipes peer was closed, signaling the process exited.
-  if (::poll(&poll_fd, 1, timeout_ms) == -1)
+  if (::poll(&poll_fd, 1, timeout_ms) == -1) {
+    ::free(func);
     return ProcessStatus::error("poll(2) failed");
+  }
   // If the pipe wasn't closed by the child yet then timeout has expired.
   if (!(poll_fd.revents & POLLHUP)) {
     ::kill(pid, SIGKILL);
+    ::free(func);
     return ProcessStatus::timed_out_ps();
   }
 
@@ -69,9 +77,12 @@ ProcessStatus invoke_in_subprocess(FunctionCaller *func, unsigned timeout_ms) {
   // Wait on the pid of the subprocess here so it gets collected by the system
   // and doesn't turn into a zombie.
   pid_t status = ::waitpid(pid, &wstatus, 0);
-  if (status == -1)
+  if (status == -1) {
+    ::free(func);
     return ProcessStatus::error("waitpid(2) failed");
+  }
   assert(status == pid);
+  ::free(func);
   return {wstatus};
 }
 
diff --git a/libc/test/UnitTest/FPExceptMatcher.cpp b/libc/test/UnitTest/FPExceptMatcher.cpp
index 889f9f6f44a913..928c3df6ac48a6 100644
--- a/libc/test/UnitTest/FPExceptMatcher.cpp
+++ b/libc/test/UnitTest/FPExceptMatcher.cpp
@@ -44,6 +44,7 @@ FPExceptMatcher::FPExceptMatcher(FunctionCaller *func) {
   fputil::get_env(&oldEnv);
   if (sigsetjmp(jumpBuffer, 1) == 0)
     func->call();
+  free(func);
   // We restore the previous floating point environment after
   // the call to the function which can potentially raise SIGFPE.
   fputil::set_env(&oldEnv);

[jhuber6]

Do we have some sort of RAII wrapper that could handle this? Seems a little cumbersome to track each branch.

[nickdesaulniers]

No; it's probably not too bad to add a cpp::unique_ptr to a newly created libc/src/__support/CPP/memory.h, but I'll leave that cleanup for another time when the build's not red.

[nickdesaulniers]

still fails: https://lab.llvm.org/buildbot/#/builders/171/builds/13529. Hmm...did I miss something?

[nickdesaulniers]

==3162239==ERROR: AddressSanitizer: alloc-dealloc-mismatch (operator new vs free) on 0x602000000030
    #0 0x561c514c7f72 in __interceptor_free (/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/build/libc/test/src/stdlib/libc.test.src.stdlib._Exit_test.__unit__.__build__+0xa8f72) (BuildId: 0cd81dae603618c82e6aada51fbc7571192885c3)
    #1 0x561c5151d7d0 in __llvm_libc_20_0_0_git::testutils::invoke_in_subprocess(__llvm_libc_20_0_0_git::testutils::FunctionCaller*, unsigned int) /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/UnitTest/ExecuteFunctionUnix.cpp:85:3
    #2 0x561c5151c451 in __llvm_libc_20_0_0_git::testing::Test::testProcessExits(__llvm_libc_20_0_0_git::testutils::FunctionCaller*, int, char const*, char const*, __llvm_libc_20_0_0_git::testing::internal::Location) /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/UnitTest/LibcDeathTestExecutors.cpp:72:7
    #3 0x561c51505869 in LlvmLibcStdlib__Exit::Run() /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/src/stdlib/_Exit_test.cpp:14:3
0x602000000030 is located 0 bytes inside of 16-byte region [0x602000000030,0x602000000040)
allocated by thread T0 here:
    #0 0x561c51502fed in operator new(unsigned long) (/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/build/libc/test/src/stdlib/libc.test.src.stdlib._Exit_test.__unit__.__build__+0xe3fed) (BuildId: 0cd81dae603618c82e6aada51fbc7571192885c3)
    #1 0x561c51505cd5 in __llvm_libc_20_0_0_git::testutils::FunctionCaller* __llvm_libc_20_0_0_git::testing::Test::createCallable<LlvmLibcStdlib__Exit::Run()::$_0>(LlvmLibcStdlib__Exit::Run()::$_0) /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/UnitTest/LibcTest.h:221:12
    #2 0x561c5150576f in LlvmLibcStdlib__Exit::Run() /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/src/stdlib/_Exit_test.cpp:14:3
    #3 0x561c5151ec57 in __llvm_libc_20_0_0_git::testing::Test::runTests(__llvm_libc_20_0_0_git::testing::TestOptions const&) /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/UnitTest/LibcTest.cpp:165:8
    #4 0x561c515594f8 in main /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-fullbuild-dbg-asan/llvm-project/libc/test/UnitTest/LibcTestMain.cpp:59:10
    #5 0x7f92a8246249 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

oh, do I need delete rather than free?