[sanitizer] Pre-commit disabled test for fork (llvm#75257)

Author: vitalybuka

compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.cpp

@@ -0,0 +1,90 @@
+// RUN: %clangxx -O0 %s -o %t && %env_tool_opts=die_after_fork=0 %run %t
+
+// UNSUPPORTED: asan, hwasan, lsan, msan, tsan, ubsan
+
+// Forking in multithread environment is unsupported. However we already have
+// some workarounds, and will add more, so this is the test.
+// The test try to check two things:
+//  1. Internal mutexes used by `inparent` thread do not deadlock `inchild`
+//     thread.
+//  2. Stack poisoned by `inparent` is not poisoned in `inchild` thread.
+
+#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;
+
+pthread_barrier_t bar;
+
+// Without appropriate workarounds this code can cause the forked process to
+// start with locked internal mutexes.
+void ShouldNotDeadlock() {
+  // 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 (;;)
+    ShouldNotDeadlock();
+
+  return 0;
+}
+
+NOSAN static void *inchild(void *arg) {
+  char t[kBufferSize];
+  check_mem_is_good(t, sizeof(t));
+  ShouldNotDeadlock();
+  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;
+}

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
@@ -10,15 +16,25 @@
 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>
 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__
+#endif // __SANITIZER_COMMON_SANITIZER_SPECIFIC_H__