[compiler-rt] [sanitizer] Pre-commit disabled test for fork (PR #75257)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

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

Author: Vitaly Buka (vitalybuka)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/75257.diff


2 Files Affected:

- (added) compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.cpp (+86) 
- (modified) compiler-rt/test/sanitizer_common/sanitizer_specific.h (+16) 


``````````diff
diff --git a/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.cpp b/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.cpp
new file mode 100644
index 00000000000000..d5c60bbb7c9430
--- /dev/null
+++ b/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.cpp
@@ -0,0 +1,86 @@
+// RUN: %clangxx -O0 %s -o %t && %env_tool_opts=die_after_fork=0 %run %t
+
+// UNSUPPORTED: *
+
+// Forking in multithread environment is unsupported. However we already have
+// some workarounds, and will add more, so this is the test.
+
+#include <assert.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "sanitizer_common/sanitizer_specific.h"
+
+static const size_t kBufferSize = 1 << 20;
+
+static void *background(void *arg) { return nullptr; }
+
+pthread_barrier_t bar;
+
+void CanDeadLock() {
+  // Don't bother with leaks, we try to trigger allocator or lsan deadlock.
+  __lsan::ScopedDisabler disable;
+  char *volatile p = new char[10];
+  __lsan_do_recoverable_leak_check();
+  delete[] p;
+}
+
+// Prevent stack buffer cleanup by instrumentation.
+#define NOSAN __attribute__((no_sanitize("address", "hwaddress", "memory")))
+
+NOSAN static void *inparent(void *arg) {
+  fprintf(stderr, "inparent %d\n", gettid());
+
+  char t[kBufferSize];
+  make_mem_bad(t, sizeof(t));
+
+  pthread_barrier_wait(&bar);
+
+  for (;;)
+    CanDeadLock();
+
+  return 0;
+}
+
+NOSAN static void *inchild(void *arg) {
+  char t[kBufferSize];
+  check_mem_is_good(t, sizeof(t));
+  CanDeadLock();
+  return 0;
+}
+
+int main(void) {
+  pid_t pid;
+
+  pthread_barrier_init(&bar, nullptr, 2);
+  pthread_t thread_id;
+  while (pthread_create(&thread_id, 0, &inparent, 0) != 0) {
+  }
+  pthread_barrier_wait(&bar);
+
+  pid = fork();
+  switch (pid) {
+  case -1:
+    perror("fork");
+    return -1;
+  case 0:
+    while (pthread_create(&thread_id, 0, &inchild, 0) != 0) {
+    }
+    break;
+  default: {
+    fprintf(stderr, "fork %d\n", pid);
+    int status;
+    while (waitpid(-1, &status, __WALL) != pid) {
+    }
+    assert(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+    break;
+  }
+  }
+
+  return 0;
+}
\ No newline at end of file
diff --git a/compiler-rt/test/sanitizer_common/sanitizer_specific.h b/compiler-rt/test/sanitizer_common/sanitizer_specific.h
index 1a802020cfd668..963d91cb305f60 100644
--- a/compiler-rt/test/sanitizer_common/sanitizer_specific.h
+++ b/compiler-rt/test/sanitizer_common/sanitizer_specific.h
@@ -1,6 +1,12 @@
 #ifndef __SANITIZER_COMMON_SANITIZER_SPECIFIC_H__
 #define __SANITIZER_COMMON_SANITIZER_SPECIFIC_H__
 
+#include <sanitizer/lsan_interface.h>
+
+__attribute__((weak)) int __lsan_do_recoverable_leak_check() { return 0; }
+__attribute__((weak)) void __lsan_disable(void) {}
+__attribute__((weak)) void __lsan_enable(void) {}
+
 #ifndef __has_feature
 #  define __has_feature(x) 0
 #endif
@@ -10,6 +16,8 @@
 static void check_mem_is_good(void *p, size_t s) {
   __msan_check_mem_is_initialized(p, s);
 }
+static void make_mem_good(void *p, size_t s) { __msan_unpoison(p, s); }
+static void make_mem_bad(void *p, size_t s) { __msan_poison(p, s); }
 #elif __has_feature(address_sanitizer)
 #  include <sanitizer/asan_interface.h>
 #  include <stdlib.h>
@@ -17,8 +25,16 @@ static void check_mem_is_good(void *p, size_t s) {
   if (__asan_region_is_poisoned(p, s))
     abort();
 }
+static void make_mem_good(void *p, size_t s) {
+  __asan_unpoison_memory_region(p, s);
+}
+static void make_mem_bad(void *p, size_t s) {
+  __asan_poison_memory_region(p, s);
+}
 #else
 static void check_mem_is_good(void *p, size_t s) {}
+static void make_mem_good(void *p, size_t s) {}
+static void make_mem_bad(void *p, size_t s) {}
 #endif
 
 #endif // __SANITIZER_COMMON_SANITIZER_SPECIFIC_H__
\ No newline at end of file

``````````

</details>


https://github.com/llvm/llvm-project/pull/75257