[PATCH] D17639: [asan] Fix recvfrom.cc testcase failure in large parallel tests run.

[Maxim Ostapenko via llvm-commits]

m.ostapenko created this revision.
m.ostapenko added reviewers: kcc, samsonov, eugenis, dvyukov.
m.ostapenko added subscribers: llvm-commits, ygribov.
m.ostapenko set the repository for this revision to rL LLVM.

This testcase currently fails on sanitizer-x86_64-linux buildbot with following error:

```
FAIL: AddressSanitizer-i386-linux :: TestCases/Linux/recvfrom.cc (524 of 1166)
******************** TEST 'AddressSanitizer-i386-linux :: TestCases/Linux/recvfrom.cc' FAILED ********************
Script:
--
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/clang_build/./bin/clang --driver-mode=g++ -fsanitize=address -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls -gline-tables-only -m32 /mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/projects/compiler-rt/test/asan/TestCases/Linux/recvfrom.cc -o /mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/clang_build/projects/compiler-rt/test/asan/I386LinuxConfig/TestCases/Linux/Output/recvfrom.cc.tmp && not  /mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/clang_build/projects/compiler-rt/test/asan/I386LinuxConfig/TestCases/Linux/Output/recvfrom.cc.tmp 2>&1 | FileCheck /mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/projects/compiler-rt/test/asan/TestCases/Linux/recvfrom.cc
--
Exit Code: 2

Command Output (stderr):
--
FileCheck error: '-' is empty.

--
```
I haven't managed reproduce this on my local box, but here my thoughts about the issue:
I believe this failure happens because of race on port 1234 between AddressSanitizer-i386-linux and AddressSanitizer-x86_64-linux instances of recvfrom.cc testcase. This patch tries to resolve  the issue by trying to use another port if 1234 has already acquired.

Repository:
  rL LLVM

http://reviews.llvm.org/D17639

Files:
  test/asan/TestCases/Linux/recvfrom.cc

Index: test/asan/TestCases/Linux/recvfrom.cc
===================================================================
--- test/asan/TestCases/Linux/recvfrom.cc
+++ test/asan/TestCases/Linux/recvfrom.cc
@@ -2,7 +2,6 @@
 //
 // RUN: %clangxx_asan %s -o %t && not %run %t 2>&1 | FileCheck %s
 //
-// REQUIRES: broken
 // UNSUPPORTED: android
 
 #include <stdio.h>
@@ -14,8 +13,9 @@
 #include <sys/socket.h>
 #include <pthread.h>
 
-const int kPortNum = 1234;
+int kPortNum = 1234;
 const int kBufSize = 10;
+pthread_mutex_t server_ready_mu = PTHREAD_MUTEX_INITIALIZER;
 
 static void *server_thread_udp(void *data) {
   char buf[kBufSize / 2];
@@ -29,9 +29,15 @@
   serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
   serveraddr.sin_port = htons(kPortNum);
 
-  if (bind(sockfd, (struct sockaddr *) &serveraddr, sizeof(serveraddr)) < 0)
-    fprintf(stderr, "ERROR on binding\n");
-
+  // In parallel test run we may already have acquired port 1234. Increase
+  // kPortNum until we found free port.
+  while (bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0) {
+    ++kPortNum;
+    serveraddr.sin_port = htons(kPortNum);
+  }
+  // Release the mutex since the server is ready now and kPortNum has proper
+  // value.
+  pthread_mutex_unlock(&server_ready_mu);
   recvfrom(sockfd, buf, kBufSize, 0, NULL, NULL); // BOOM
   // CHECK: {{WRITE of size 9 at 0x.* thread T1}}
   // CHECK: {{    #1 0x.* in server_thread_udp.*recvfrom.cc:}}[[@LINE-2]]
@@ -66,6 +72,10 @@
   serveraddr.sin_family = AF_INET;
   memcpy((char *)&serveraddr.sin_addr.s_addr, (char *)server->h_addr,
           server->h_length);
+
+  // Wait until the server found free port and initialized kPortNum with proper
+  // value.
+  pthread_mutex_lock(&server_ready_mu);
   serveraddr.sin_port = htons(kPortNum);
   sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr *) &serveraddr,
          sizeof(serveraddr));


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