[msan] Reorder unittests for future parametrization.

[vitalybuka]

Summary

[msan] Wrap sockaddr_in and socket for future IPv6 support.

[msan] Choose in runtime if IPv4 or IPv6 are supported.

This reverts commit cab5051c691ce27a7ffac41e8e76ceb222ad9549.

[msan] Replace AF_INET with AF_UNIX to avoid IPv4 vs IPv6 issues.

This reverts commit 79cf16bf224d6ac9fb9e0356c5947ebc4fd6ff92.

[msan] Make test to fall-back to IPv6 if IPv4 is not available.

[tsan] Fall-back to IPv6 if IPv4 is not available.

lib/msan/tests/CMakeLists.txt

set(MSAN_UNITTEST_COMMON_CFLAGS
   -fno-exceptions
   -fno-omit-frame-pointer
   -mno-omit-leaf-frame-pointer
   -Wno-deprecated-declarations
   -Wno-unused-variable
   -Wno-zero-length-array
   -Wno-uninitialized
   -Werror=sign-compare
+  -Wno-gnu-zero-variadic-macro-arguments
 )
 set(MSAN_UNITTEST_INSTRUMENTED_CFLAGS
   ${MSAN_UNITTEST_COMMON_CFLAGS}
   -fsanitize=memory
   -fsanitize-memory-track-origins
   -mllvm -msan-keep-going=1
 )
 set(MSAN_UNITTEST_LINK_FLAGS

lib/msan/tests/msan_test.cc

 
 template<typename T>
 void ExpectPoisonedWithOrigin(const T& t, unsigned origin) {
   EXPECT_NE(-1, __msan_test_shadow((void*)&t, sizeof(t)));
   if (TrackingOrigins()) EXPECT_ORIGIN(origin, __msan_get_origin((void *)&t));
 }
 
 #define EXPECT_NOT_POISONED(x) EXPECT_EQ(true, TestForNotPoisoned((x)))
+#define EXPECT_NOT_POISONED2(data, size) \
+  EXPECT_EQ(true, TestForNotPoisoned((data), (size)))
+
+bool TestForNotPoisoned(const void *data, size_t size) {
+  return __msan_test_shadow(data, size) == -1;
+}
 
 template<typename T>
 bool TestForNotPoisoned(const T& t) {
-  return __msan_test_shadow((void*)&t, sizeof(t)) == -1;
+  return TestForNotPoisoned((void *)&t, sizeof(t));
 }
 
 static U8 poisoned_array[100];
 template<class T>
 T *GetPoisoned(int i = 0, T val = 0) {
   T *res = (T*)&poisoned_array[i];
   *res = val;
   __msan_poison(&poisoned_array[i], sizeof(T));
TEST(MemorySanitizer, bind_getsockname) {
   res = getsockname(sock, (struct sockaddr *)&buf, &addrlen);
   EXPECT_NOT_POISONED(addrlen);
   EXPECT_NOT_POISONED(buf[0]);
   EXPECT_NOT_POISONED(buf[addrlen - 1]);
   EXPECT_POISONED(buf[addrlen]);
   close(sock);
 }
 
-TEST(MemorySanitizer, accept) {
-  int listen_socket = socket(AF_INET, SOCK_STREAM, 0);
+class SocketAddr {
+ public:
+  virtual ~SocketAddr() = default;
+  virtual struct sockaddr *ptr() = 0;
+  virtual size_t size() const = 0;
+};
+
+class SocketAddr4 : public SocketAddr {
+ public:
+  SocketAddr4() { EXPECT_POISONED(sai_); }
+  explicit SocketAddr4(uint16_t port) {
+    memset(&sai_, 0, sizeof(sai_));
+    sai_.sin_family = AF_INET;
+    sai_.sin_port = port;
+    sai_.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  }
+
+  sockaddr *ptr() override { return reinterpret_cast<sockaddr *>(&sai_); }
+
+  size_t size() const override { return sizeof(sai_); }
+
+ private:
+  sockaddr_in sai_;
+};
+
+class SocketAddr6 : public SocketAddr {
+ public:
+  SocketAddr6() { EXPECT_POISONED(sai_); }
+  explicit SocketAddr6(uint16_t port) {
+    memset(&sai_, 0, sizeof(sai_));
+    sai_.sin6_family = AF_INET6;
+    sai_.sin6_port = port;
+    sai_.sin6_addr = in6addr_loopback;
+  }
+
+  sockaddr *ptr() override { return reinterpret_cast<sockaddr *>(&sai_); }
+
+  size_t size() const override { return sizeof(sai_); }
+
+ private:
+  sockaddr_in6 sai_;
+};
+
+class MemorySanitizerIpTest : public ::testing::TestWithParam<int> {
+ public:
+  void SetUp() override {
+    ASSERT_TRUE(GetParam() == AF_INET || GetParam() == AF_INET6);
+  }
+
+  template <class... Args>
+  std::unique_ptr<SocketAddr> CreateSockAddr(Args... args) const {
+    if (GetParam() == AF_INET)
+      return std::unique_ptr<SocketAddr>(new SocketAddr4(args...));
+    return std::unique_ptr<SocketAddr>(new SocketAddr6(args...));
+  }
+
+  int CreateSocket(int socket_type) const {
+    return socket(GetParam(), socket_type, 0);
+  }
+};
+
+std::vector<int> GetAvailableIpSocketFamilies() {
+  std::vector<int> result;
+
+  for (int i : std::vector<int>(AF_INET, AF_INET6)) {
+    int s = socket(i, SOCK_STREAM, 0);
+    if (s > 0) {
+      result.push_back(i);
+      close(s);
+    }
+  }
+
+  return result;
+}
+
+INSTANTIATE_TEST_CASE_P(IpTests, MemorySanitizerIpTest,
+                        ::testing::ValuesIn(GetAvailableIpSocketFamilies()));
+
+TEST_P(MemorySanitizerIpTest, accept) {
+  int listen_socket = CreateSocket(SOCK_STREAM);
   ASSERT_LT(0, listen_socket);
 
-  struct sockaddr_in sai;
-  memset(&sai, 0, sizeof(sai));
-  sai.sin_family = AF_INET;
-  sai.sin_port = 0;
-  sai.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-  int res = bind(listen_socket, (struct sockaddr *)&sai, sizeof(sai));
+  auto sai = CreateSockAddr(0);
+  int res = bind(listen_socket, sai->ptr(), sai->size());
   ASSERT_EQ(0, res);
 
   res = listen(listen_socket, 1);
   ASSERT_EQ(0, res);
 
-  socklen_t sz = sizeof(sai);
-  res = getsockname(listen_socket, (struct sockaddr *)&sai, &sz);
+  socklen_t sz = sai->size();
+  res = getsockname(listen_socket, sai->ptr(), &sz);
   ASSERT_EQ(0, res);
-  ASSERT_EQ(sizeof(sai), sz);
+  ASSERT_EQ(sai->size(), sz);
 
-  int connect_socket = socket(AF_INET, SOCK_STREAM, 0);
+  int connect_socket = CreateSocket(SOCK_STREAM);
   ASSERT_LT(0, connect_socket);
   res = fcntl(connect_socket, F_SETFL, O_NONBLOCK);
   ASSERT_EQ(0, res);
-  res = connect(connect_socket, (struct sockaddr *)&sai, sizeof(sai));
+  res = connect(connect_socket, sai->ptr(), sai->size());
   // On FreeBSD this connection completes immediately.
   if (res != 0) {
     ASSERT_EQ(-1, res);
     ASSERT_EQ(EINPROGRESS, errno);
   }
 
-  __msan_poison(&sai, sizeof(sai));
-  int new_sock = accept(listen_socket, (struct sockaddr *)&sai, &sz);
+  __msan_poison(sai->ptr(), sai->size());
+  int new_sock = accept(listen_socket, sai->ptr(), &sz);
   ASSERT_LT(0, new_sock);
-  ASSERT_EQ(sizeof(sai), sz);
-  EXPECT_NOT_POISONED(sai);
+  ASSERT_EQ(sai->size(), sz);
+  EXPECT_NOT_POISONED2(sai->ptr(), sai->size());
 
-  __msan_poison(&sai, sizeof(sai));
-  res = getpeername(new_sock, (struct sockaddr *)&sai, &sz);
+  __msan_poison(sai->ptr(), sai->size());
+  res = getpeername(new_sock, sai->ptr(), &sz);
   ASSERT_EQ(0, res);
-  ASSERT_EQ(sizeof(sai), sz);
-  EXPECT_NOT_POISONED(sai);
+  ASSERT_EQ(sai->size(), sz);
+  EXPECT_NOT_POISONED2(sai->ptr(), sai->size());
 
   close(new_sock);
   close(connect_socket);
   close(listen_socket);
 }
 
-TEST(MemorySanitizer, getaddrinfo) {
-  struct addrinfo *ai;
-  struct addrinfo hints;
-  memset(&hints, 0, sizeof(hints));
-  hints.ai_family = AF_INET;
-  int res = getaddrinfo("localhost", NULL, &hints, &ai);
+TEST_P(MemorySanitizerIpTest, recvmsg) {
+  int server_socket = CreateSocket(SOCK_DGRAM);
+  ASSERT_LT(0, server_socket);
+
+  auto sai = CreateSockAddr(0);
+  int res = bind(server_socket, sai->ptr(), sai->size());
   ASSERT_EQ(0, res);
-  EXPECT_NOT_POISONED(*ai);
-  ASSERT_EQ(sizeof(sockaddr_in), ai->ai_addrlen);
-  EXPECT_NOT_POISONED(*(sockaddr_in*)ai->ai_addr); 
-}
 
-TEST(MemorySanitizer, getnameinfo) {
-  struct sockaddr_in sai;
-  memset(&sai, 0, sizeof(sai));
-  sai.sin_family = AF_INET;
-  sai.sin_port = 80;
-  sai.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-  char host[500];
-  char serv[500];
-  int res = getnameinfo((struct sockaddr *)&sai, sizeof(sai), host,
-                        sizeof(host), serv, sizeof(serv), 0);
+  socklen_t sz = sai->size();
+  res = getsockname(server_socket, sai->ptr(), &sz);
   ASSERT_EQ(0, res);
-  EXPECT_NOT_POISONED(host[0]);
-  EXPECT_POISONED(host[sizeof(host) - 1]);
+  ASSERT_EQ(sai->size(), sz);
 
-  ASSERT_NE(0U, strlen(host));
-  EXPECT_NOT_POISONED(serv[0]);
-  EXPECT_POISONED(serv[sizeof(serv) - 1]);
-  ASSERT_NE(0U, strlen(serv));
+  int client_socket = CreateSocket(SOCK_DGRAM);
+  ASSERT_LT(0, client_socket);
+
+  auto client_sai = CreateSockAddr(0);
+  res = bind(client_socket, client_sai->ptr(), client_sai->size());
+  ASSERT_EQ(0, res);
+
+  sz = client_sai->size();
+  res = getsockname(client_socket, client_sai->ptr(), &sz);
+  ASSERT_EQ(0, res);
+  ASSERT_EQ(client_sai->size(), sz);
+
+  const char *s = "message text";
+  struct iovec iov;
+  iov.iov_base = (void *)s;
+  iov.iov_len = strlen(s) + 1;
+  struct msghdr msg;
+  memset(&msg, 0, sizeof(msg));
+  msg.msg_name = sai->ptr();
+  msg.msg_namelen = sai->size();
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+  res = sendmsg(client_socket, &msg, 0);
+  ASSERT_LT(0, res);
+
+  char buf[1000];
+  struct iovec recv_iov;
+  recv_iov.iov_base = (void *)&buf;
+  recv_iov.iov_len = sizeof(buf);
+  auto recv_sai = CreateSockAddr();
+  struct msghdr recv_msg;
+  memset(&recv_msg, 0, sizeof(recv_msg));
+  recv_msg.msg_name = recv_sai->ptr();
+  recv_msg.msg_namelen = recv_sai->size();
+  recv_msg.msg_iov = &recv_iov;
+  recv_msg.msg_iovlen = 1;
+  res = recvmsg(server_socket, &recv_msg, 0);
+  ASSERT_LT(0, res);
+
+  ASSERT_EQ(recv_sai->size(), recv_msg.msg_namelen);
+  EXPECT_NOT_POISONED2(recv_sai->ptr(), recv_sai->size());
+  EXPECT_STREQ(s, buf);
+
+  close(server_socket);
+  close(client_socket);
 }
 
 #define EXPECT_HOSTENT_NOT_POISONED(he)        \
   do {                                         \
     EXPECT_NOT_POISONED(*(he));                \
-    ASSERT_NE((void *) 0, (he)->h_name);       \
-    ASSERT_NE((void *) 0, (he)->h_aliases);    \
-    ASSERT_NE((void *) 0, (he)->h_addr_list);  \
+    ASSERT_NE((void *)0, (he)->h_name);        \
+    ASSERT_NE((void *)0, (he)->h_aliases);     \
+    ASSERT_NE((void *)0, (he)->h_addr_list);   \
     EXPECT_NOT_POISONED(strlen((he)->h_name)); \
     char **p = (he)->h_aliases;                \
     while (*p) {                               \
       EXPECT_NOT_POISONED(strlen(*p));         \
       ++p;                                     \
     }                                          \
     char **q = (he)->h_addr_list;              \
     while (*q) {                               \

 #ifndef MSAN_TEST_DISABLE_GETHOSTBYNAME
 
 TEST(MemorySanitizer, gethostbyname) {
   struct hostent *he = gethostbyname("localhost");
   ASSERT_NE((void *)NULL, he);
   EXPECT_HOSTENT_NOT_POISONED(he);
 }
 
-#endif // MSAN_TEST_DISABLE_GETHOSTBYNAME
+#endif  // MSAN_TEST_DISABLE_GETHOSTBYNAME
 
-TEST(MemorySanitizer, recvmsg) {
-  int server_socket = socket(AF_INET, SOCK_DGRAM, 0);
-  ASSERT_LT(0, server_socket);
+TEST(MemorySanitizer, getaddrinfo) {
+  struct addrinfo *ai;
+  struct addrinfo hints;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_INET;
+  int res = getaddrinfo("localhost", NULL, &hints, &ai);
+  ASSERT_EQ(0, res);
+  EXPECT_NOT_POISONED(*ai);
+  ASSERT_EQ(sizeof(sockaddr_in), ai->ai_addrlen);
+  EXPECT_NOT_POISONED(*(sockaddr_in *)ai->ai_addr);
+}
 
+TEST(MemorySanitizer, getnameinfo) {
   struct sockaddr_in sai;
   memset(&sai, 0, sizeof(sai));
   sai.sin_family = AF_INET;
-  sai.sin_port = 0;
+  sai.sin_port = 80;
   sai.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-  int res = bind(server_socket, (struct sockaddr *)&sai, sizeof(sai));
-  ASSERT_EQ(0, res);
-
-  socklen_t sz = sizeof(sai);
-  res = getsockname(server_socket, (struct sockaddr *)&sai, &sz);
-  ASSERT_EQ(0, res);
-  ASSERT_EQ(sizeof(sai), sz);
-
-
-  int client_socket = socket(AF_INET, SOCK_DGRAM, 0);
-  ASSERT_LT(0, client_socket);
-
-  struct sockaddr_in client_sai;
-  memset(&client_sai, 0, sizeof(client_sai));
-  client_sai.sin_family = AF_INET;
-  client_sai.sin_port = 0;
-  client_sai.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-  res = bind(client_socket, (struct sockaddr *)&client_sai, sizeof(client_sai));
-  ASSERT_EQ(0, res);
-
-  sz = sizeof(client_sai);
-  res = getsockname(client_socket, (struct sockaddr *)&client_sai, &sz);
+  char host[500];
+  char serv[500];
+  int res = getnameinfo((struct sockaddr *)&sai, sizeof(sai), host,
+                        sizeof(host), serv, sizeof(serv), 0);
   ASSERT_EQ(0, res);
-  ASSERT_EQ(sizeof(client_sai), sz);
-
-  const char *s = "message text";
-  struct iovec iov;
-  iov.iov_base = (void *)s;
-  iov.iov_len = strlen(s) + 1;
-  struct msghdr msg;
-  memset(&msg, 0, sizeof(msg));
-  msg.msg_name = &sai;
-  msg.msg_namelen = sizeof(sai);
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-  res = sendmsg(client_socket, &msg, 0);
-  ASSERT_LT(0, res);
-
-
-  char buf[1000];
-  struct iovec recv_iov;
-  recv_iov.iov_base = (void *)&buf;
-  recv_iov.iov_len = sizeof(buf);
-  struct sockaddr_in recv_sai;
-  struct msghdr recv_msg;
-  memset(&recv_msg, 0, sizeof(recv_msg));
-  recv_msg.msg_name = &recv_sai;
-  recv_msg.msg_namelen = sizeof(recv_sai);
-  recv_msg.msg_iov = &recv_iov;
-  recv_msg.msg_iovlen = 1;
-  res = recvmsg(server_socket, &recv_msg, 0);
-  ASSERT_LT(0, res);
-
-  ASSERT_EQ(sizeof(recv_sai), recv_msg.msg_namelen);
-  EXPECT_NOT_POISONED(*(struct sockaddr_in *)recv_msg.msg_name);
-  EXPECT_STREQ(s, buf);
+  EXPECT_NOT_POISONED(host[0]);
+  EXPECT_POISONED(host[sizeof(host) - 1]);
 
-  close(server_socket);
-  close(client_socket);
+  ASSERT_NE(0U, strlen(host));
+  EXPECT_NOT_POISONED(serv[0]);
+  EXPECT_POISONED(serv[sizeof(serv) - 1]);
+  ASSERT_NE(0U, strlen(serv));
 }
 
 TEST(MemorySanitizer, gethostbyname2) {
   struct hostent *he = gethostbyname2("localhost", AF_INET);
   ASSERT_NE((void *)NULL, he);
   EXPECT_HOSTENT_NOT_POISONED(he);
 }
 

test/msan/Linux/sendmsg.cc

 const int kBufSize = 10;
 int sockfd;
 
 int main() {
   int ret;
   char buf[kBufSize] = {0};
   pthread_t client_thread;
   struct sockaddr_in serveraddr;
-
-  sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+  struct sockaddr_in6 serveraddr6;
 
   memset(&serveraddr, 0, sizeof(serveraddr));
   serveraddr.sin_family = AF_INET;
   serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
   serveraddr.sin_port = 0;
-
-  bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
+  struct sockaddr *addr = (struct sockaddr *)&serveraddr;
   socklen_t addrlen = sizeof(serveraddr);
-  getsockname(sockfd, (struct sockaddr *)&serveraddr, &addrlen);
+
+  sockfd = socket(addr->sa_family, SOCK_DGRAM, 0);
+  if (sockfd <= 0) {
+    // Try to fall-back to IPv6
+    memset(&serveraddr6, 0, sizeof(serveraddr6));
+    serveraddr6.sin6_family = AF_INET6;
+    serveraddr6.sin6_addr = in6addr_any;
+    serveraddr6.sin6_port = 0;
+    addr = (struct sockaddr *)&serveraddr6;
+    addrlen = sizeof(serveraddr6);
+
+    sockfd = socket(addr->sa_family, SOCK_DGRAM, 0);
+  }
+  assert(sockfd > 0);
+
+  bind(sockfd, addr, addrlen);
+  getsockname(sockfd, addr, &addrlen);
 
 #if defined(POISON)
   __msan_poison(buf + 7, 1);
 #endif
 
 #if defined(SENDMSG)
   struct iovec iov[2] = {{buf, 5}, {buf + 5, 5}};
   struct msghdr msg;
-  msg.msg_name = &serveraddr;
+  msg.msg_name = addr;
   msg.msg_namelen = addrlen;
   msg.msg_iov = iov;
   msg.msg_iovlen = 2;
   msg.msg_control = 0;
   msg.msg_controllen = 0;
   msg.msg_flags = 0;
 #endif
 
 #if defined(SEND)
-  ret = connect(sockfd, (struct sockaddr *)&serveraddr, addrlen);
+  ret = connect(sockfd, addr, addrlen);
   assert(ret == 0);
   ret = send(sockfd, buf, kBufSize, 0);
   // SEND: Uninitialized bytes in __interceptor_send at offset 7 inside [{{.*}}, 10)
   assert(ret > 0);
 #elif defined(SENDTO)
-  ret =
-      sendto(sockfd, buf, kBufSize, 0, (struct sockaddr *)&serveraddr, addrlen);
+  ret = sendto(sockfd, buf, kBufSize, 0, addr, addrlen);
   // SENDTO: Uninitialized bytes in __interceptor_sendto at offset 7 inside [{{.*}}, 10)
   assert(ret > 0);
 #elif defined(SENDMSG)
   ret = sendmsg(sockfd, &msg, 0);
   // SENDMSG: Uninitialized bytes in {{.*}} at offset 2 inside [{{.*}}, 5)
   assert(ret > 0);
 #endif
   fprintf(stderr, "== done\n");
   // NEGATIVE: == done
   return 0;
 }

test/msan/ioctl.cc

 // RUN: %clangxx_msan -O0 -g %s -o %t && %run %t
 // RUN: %clangxx_msan -O3 -g %s -o %t && %run %t
 
 #include <assert.h>
 #include <stdlib.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <unistd.h>
 
 int main(int argc, char **argv) {
-  int fd = socket(AF_INET, SOCK_DGRAM, 0);
+  int fd = socket(AF_UNIX, SOCK_DGRAM, 0);
 
   unsigned int z;
   int res = ioctl(fd, FIOGETOWN, &z);
   assert(res == 0);
   close(fd);
   if (z)
     exit(0);
   return 0;
 }

test/msan/ioctl_custom.cc

 // RUN: %clangxx_msan -O0 -g %s -o %t && %run %t
 // RUN: %clangxx_msan -O3 -g %s -o %t && %run %t
 
 // RUN: %clangxx_msan -DPOSITIVE -O0 -g %s -o %t && not %run %t 2>&1 | FileCheck %s
 // RUN: %clangxx_msan -DPOSITIVE -O3 -g %s -o %t && not %run %t 2>&1 | FileCheck %s
 
 #include <assert.h>
 #include <stdlib.h>
 #include <net/if.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <unistd.h>
 
 int main(int argc, char **argv) {
-  int fd = socket(AF_INET, SOCK_STREAM, 0);
+  int fd = socket(AF_UNIX, SOCK_STREAM, 0);
 
   struct ifreq ifreqs[20];
   struct ifconf ifc;
   ifc.ifc_ifcu.ifcu_req = ifreqs;
 #ifndef POSITIVE
   ifc.ifc_len = sizeof(ifreqs);
 #endif
   int res = ioctl(fd, SIOCGIFCONF, (void *)&ifc);
   // CHECK: Uninitialized bytes in ioctl{{.*}} at offset 0 inside [0x{{.*}}, 4)
   // CHECK: WARNING: MemorySanitizer: use-of-uninitialized-value
   // CHECK: #{{.*}} in main {{.*}}ioctl_custom.cc:[[@LINE-3]]
   assert(res == 0);
   for (int i = 0; i < ifc.ifc_len / sizeof(*ifc.ifc_ifcu.ifcu_req); ++i)
     printf("%d  %zu  %s\n", i, strlen(ifreqs[i].ifr_name), ifreqs[i].ifr_name);
   return 0;
 }

test/tsan/fd_socket_connect_norace.cc

 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+#include <arpa/inet.h>
+#include <assert.h>
+#include <netinet/in.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
 #include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
+#include <sys/types.h>
+#include <unistd.h>
 
-struct sockaddr_in addr;
+struct sockaddr_in addr4;
+struct sockaddr_in6 addr6;
+struct sockaddr *addr;
+socklen_t addrlen;
 int X;
 
 void *ClientThread(void *x) {
-  int c = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+  int c = socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
   X = 42;
-  if (connect(c, (struct sockaddr*)&addr, sizeof(addr))) {
+  if (connect(c, addr, addrlen)) {
     perror("connect");
     exit(1);
   }
   close(c);
   return NULL;
 }
 
 int main() {
-  int s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-  addr.sin_family = AF_INET;
-  inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);
-  addr.sin_port = INADDR_ANY;
-  socklen_t len = sizeof(addr);
-  bind(s, (sockaddr*)&addr, len);
-  getsockname(s, (sockaddr*)&addr, &len);
+  addr4.sin_family = AF_INET;
+  addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  addr4.sin_port = INADDR_ANY;
+  addr = (struct sockaddr *)&addr4;
+  addrlen = sizeof(addr4);
+
+  int s = socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
+  if (s <= 0) {
+    // Try to fall-back to IPv6
+    addr6.sin6_family = AF_INET6;
+    addr6.sin6_addr = in6addr_loopback;
+    addr6.sin6_port = INADDR_ANY;
+    addr = (struct sockaddr *)&addr6;
+    addrlen = sizeof(addr6);
+    s = socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
+  }
+  assert(s > 0);
+
+  bind(s, addr, addrlen);
+  getsockname(s, addr, &addrlen);
   listen(s, 10);
   pthread_t t;
   pthread_create(&t, 0, ClientThread, 0);
   int c = accept(s, 0, 0);
   X = 42;
   pthread_join(t, 0);
   close(c);
   close(s);
   fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
 

test/tsan/fd_socket_norace.cc

 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+#include <arpa/inet.h>
+#include <assert.h>
+#include <netinet/in.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
 #include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
+#include <sys/types.h>
+#include <unistd.h>
 
-struct sockaddr_in addr;
+struct sockaddr_in addr4;
+struct sockaddr_in6 addr6;
+struct sockaddr *addr;
+socklen_t addrlen;
 int X;
 
 void *ClientThread(void *x) {
   X = 42;
-  int c = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-  if (connect(c, (struct sockaddr*)&addr, sizeof(addr))) {
+  int c = socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
+  if (connect(c, addr, addrlen)) {
     perror("connect");
     exit(1);
   }
   if (send(c, "a", 1, 0) != 1) {
     perror("send");
     exit(1);
   }
   close(c);
   return NULL;
 }
 
 int main() {
-  int s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-  addr.sin_family = AF_INET;
-  inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);
-  addr.sin_port = INADDR_ANY;
-  socklen_t len = sizeof(addr);
-  bind(s, (sockaddr*)&addr, len);
-  getsockname(s, (sockaddr*)&addr, &len);
+  addr4.sin_family = AF_INET;
+  addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  addr4.sin_port = INADDR_ANY;
+  addr = (struct sockaddr *)&addr4;
+  addrlen = sizeof(addr4);
+
+  int s = socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
+  if (s <= 0) {
+    // Try to fall-back to IPv6
+    addr6.sin6_family = AF_INET6;
+    addr6.sin6_addr = in6addr_loopback;
+    addr6.sin6_port = INADDR_ANY;
+    addr = (struct sockaddr *)&addr6;
+    addrlen = sizeof(addr6);
+    s = socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
+  }
+  assert(s > 0);
+
+  bind(s, addr, addrlen);
+  getsockname(s, addr, &addrlen);
   listen(s, 10);
   pthread_t t;
   pthread_create(&t, 0, ClientThread, 0);
   int c = accept(s, 0, 0);
   char buf;
   while (read(c, &buf, 1) != 1) {
   }
   X = 43;
   close(c);
   close(s);
   pthread_join(t, 0);
   fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race