[glibc] malloc/tst-mallocfork2: Kill lingering process for unexpected failures

[glibc] malloc/tst-mallocfork2: Kill lingering process for unexpected failures

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5c8aa3849a58f2ef1d12ffb638a98578fbf99172

commit 5c8aa3849a58f2ef1d12ffb638a98578fbf99172
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Thu Feb 20 14:37:04 2020 -0300

    malloc/tst-mallocfork2: Kill lingering process for unexpected failures
    
    If the test fails due some unexpected failure after the children
    creation, either in the signal handler by calling abort or in the main
    loop; the created children might not be killed properly.
    
    This patches fixes it by:
    
      * Avoid aborting in the signal handler by setting a flag that
        an error has occured and add a check in the main loop.
    
      * Add a atexit handler to handle kill child processes.
    
    Checked on x86_64-linux-gnu.

Diff:
---
 malloc/tst-mallocfork2.c | 39 ++++++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/malloc/tst-mallocfork2.c b/malloc/tst-mallocfork2.c
index 0602a94..fc1fd64 100644
--- a/malloc/tst-mallocfork2.c
+++ b/malloc/tst-mallocfork2.c
@@ -62,6 +62,9 @@ static volatile sig_atomic_t sigusr1_received;
    progress.  Checked by liveness_signal_handler.  */
 static volatile sig_atomic_t progress_indicator = 1;
 
+/* Set to 1 if an error occurs in the signal handler.  */
+static volatile sig_atomic_t error_indicator = 0;
+
 static void
 sigusr1_handler (int signo)
 {
@@ -72,7 +75,8 @@ sigusr1_handler (int signo)
   if (pid == -1)
     {
       write_message ("error: fork\n");
-      abort ();
+      error_indicator = 1;
+      return;
     }
   if (pid == 0)
     _exit (0);
@@ -81,12 +85,14 @@ sigusr1_handler (int signo)
   if (ret < 0)
     {
       write_message ("error: waitpid\n");
-      abort ();
+      error_indicator = 1;
+      return;
     }
   if (status != 0)
     {
       write_message ("error: unexpected exit status from subprocess\n");
-      abort ();
+      error_indicator = 1;
+      return;
     }
 }
 
@@ -122,9 +128,25 @@ signal_sender (int signo, bool sleep)
     }
 }
 
+/* Children processes.  */
+static pid_t sigusr1_sender_pids[5] = { 0 };
+static pid_t sigusr2_sender_pid = 0;
+
+static void
+kill_children (void)
+{
+  for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i)
+    if (sigusr1_sender_pids[i] > 0)
+      kill (sigusr1_sender_pids[i], SIGKILL);
+  if (sigusr2_sender_pid > 0)
+    kill (sigusr2_sender_pid, SIGKILL);
+}
+
 static int
 do_test (void)
 {
+  atexit (kill_children);
+
   /* shared->barrier is intialized along with sigusr1_sender_pids
      below.  */
   shared = support_shared_allocate (sizeof (*shared));
@@ -148,14 +170,13 @@ do_test (void)
       return 1;
     }
 
-  pid_t sigusr2_sender_pid = xfork ();
+  sigusr2_sender_pid = xfork ();
   if (sigusr2_sender_pid == 0)
     signal_sender (SIGUSR2, true);
 
   /* Send SIGUSR1 signals from several processes.  Hopefully, one
      signal will hit one of the ciritical functions.  Use a barrier to
      avoid sending signals while not running fork/free/malloc.  */
-  pid_t sigusr1_sender_pids[5];
   {
     pthread_barrierattr_t attr;
     xpthread_barrierattr_init (&attr);
@@ -166,7 +187,7 @@ do_test (void)
   }
   for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i)
     {
-      sigusr1_sender_pids[i] = fork ();
+      sigusr1_sender_pids[i] = xfork ();
       if (sigusr1_sender_pids[i] == 0)
         signal_sender (SIGUSR1, false);
     }
@@ -211,7 +232,7 @@ do_test (void)
         ++malloc_signals;
       xpthread_barrier_wait (&shared->barrier);
 
-      if (objects[slot] == NULL)
+      if (objects[slot] == NULL || error_indicator != 0)
         {
           printf ("error: malloc: %m\n");
           for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i)
@@ -225,10 +246,6 @@ do_test (void)
   for (int slot = 0; slot < malloc_objects; ++slot)
     free (objects[slot]);
 
-  for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i)
-    kill (sigusr1_sender_pids[i], SIGKILL);
-  kill (sigusr2_sender_pid, SIGKILL);
-
   printf ("info: signals received during fork: %u\n", fork_signals);
   printf ("info: signals received during free: %u\n", free_signals);
   printf ("info: signals received during malloc: %u\n", malloc_signals);