Fix panic due to early transition to Closed.

The code in rcv.consumeSegment incorrectly transitions to
CLOSED state from LAST-ACK before the final ACK for the FIN.

Further if receiving a segment changes a socket to a closed state
then we should not invoke the sender as the socket is now closed
and sending any segments is incorrect.

PiperOrigin-RevId: 283625300

2 files changed, 24 insertions, 0 deletions

diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 2dd115409..a865e8857 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -2142,6 +2142,7 @@ cc_library(
         ":socket_test_util",
         "//test/util:test_util",
         "//test/util:thread_util",
+        "@com_google_absl//absl/time",
         "@com_google_googletest//:gtest",
     ],
     alwayslink = 1,
diff --git a/test/syscalls/linux/socket_ip_tcp_generic.cc b/test/syscalls/linux/socket_ip_tcp_generic.cc
index a37b49447..c74273436 100644
--- a/test/syscalls/linux/socket_ip_tcp_generic.cc
+++ b/test/syscalls/linux/socket_ip_tcp_generic.cc
@@ -24,6 +24,8 @@
 #include <sys/un.h>
 
 #include "gtest/gtest.h"
+#include "absl/time/clock.h"
+#include "absl/time/time.h"
 #include "test/syscalls/linux/socket_test_util.h"
 #include "test/util/test_util.h"
 #include "test/util/thread_util.h"
@@ -789,5 +791,26 @@ TEST_P(TCPSocketPairTest, SetTCPLingerTimeout) {
   EXPECT_EQ(get, kTCPLingerTimeout);
 }
 
+TEST_P(TCPSocketPairTest, TestTCPCloseWithData) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  ScopedThread t([&]() {
+    // Close one end to trigger sending of a FIN.
+    ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_WR), SyscallSucceeds());
+    char buf[3];
+    ASSERT_THAT(read(sockets->second_fd(), buf, 3),
+                SyscallSucceedsWithValue(3));
+    absl::SleepFor(absl::Milliseconds(50));
+    ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());
+  });
+
+  absl::SleepFor(absl::Milliseconds(50));
+  // Send some data then close.
+  constexpr char kStr[] = "abc";
+  ASSERT_THAT(write(sockets->first_fd(), kStr, 3), SyscallSucceedsWithValue(3));
+  t.Join();
+  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());
+}
+
 }  // namespace testing
 }  // namespace gvisor