Attachment 4789 Details for Bug 11588 – [PATCH 4/4 V2] pi-condvars: tst-condpi2.c, detect priority inversion

[patch] [PATCH 4/4 V2] pi-condvars: tst-condpi2.c, detect priority inversion

0004-pi-condvars-tst-condpi2.c-detect-priority-inversion.patch (text/plain), 4.42 KB, created by Darren Hart on 2010-05-13 08:13:15 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Darren Hart

Created: 2010-05-13 08:13:15 UTC

Size: 4.42 KB

patch

obsolete

>From c3a903907102c6d666be30866bc1d0b097709147 Mon Sep 17 00:00:00 2001
>From: Darren Hart <dvhltc@us.ibm.com>
>Date: Thu, 13 May 2010 01:46:46 -0400
>Subject: [PATCH 4/4] pi-condvars: tst-condpi2.c, detect priority inversion
>
>The test framework will abort the test after 2 seconds and stop a make check
>run. I had originally thought to detect the inversion and gracefully exit. I'm
>not sure which approach is preferred, so this patch adds the detection
>separately and can be safely discarded if not desired.
>
>Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
>---
> nptl/tst-condpi2.c |   65 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 63 insertions(+), 2 deletions(-)
>
>diff --git a/nptl/tst-condpi2.c b/nptl/tst-condpi2.c
>index a94e0d6..9f4515e 100644
>--- a/nptl/tst-condpi2.c
>+++ b/nptl/tst-condpi2.c
>@@ -41,7 +41,31 @@ static pthread_mutex_t race_mut;
> static pthread_cond_t sig1, sig2, sig3;
> static pthread_mutex_t m1, m2, m3;
> 
>+static pthread_barrier_t bar;
>+
> static volatile unsigned int done = 0;
>+static unsigned int test_result = 0;
>+
>+static void *
>+watchdog_tf (void *p)
>+{
>+  int err;
>+
>+  err = pthread_barrier_wait (&bar);
>+  if (err != 0 && err != PTHREAD_BARRIER_SERIAL_THREAD)
>+    error (EXIT_FAILURE, err, "watchdog_tf: barrier wait failed");
>+
>+  /* Allow time for high_tf to set done=1 indicating a successful run.  If
>+     it is hung waiting on race_var, we set done=2 indicating failure.  med_tf
>+     will detect the 2 and indicate a failure in test_result.  */
>+  usleep (1000);
>+  if (done != 1)
>+    {
>+      usleep (500000);
>+      done = 2;
>+    }
>+  return NULL;
>+}
> 
> static void *
> low_tf (void *p)
>@@ -148,6 +172,28 @@ med_tf (void *p)
>   while (!done)
>           /* Busy wait to block low threads.  */;
> 
>+  /* If watchdog_tf has set done to 2 before high_tf has set it to 1,
>+     then the test has failed.  */
>+  if (done == 2)
>+    {
>+      puts ("med_tf: unbounded priority inversion detected.");
>+      
>+      /* low_tf and high_tf are now waiting on race_var, having missed
>+         the broadcast issued in do_test(). Wake them up now and exit
>+         gracefully.  */
>+      err = pthread_mutex_lock (&race_mut);
>+      if (err != 0)
>+        error (EXIT_FAILURE, err, "med_tf: failed to lock race_mut");      
>+      err = pthread_cond_broadcast (&race_var);
>+      if (err != 0)
>+        error (EXIT_FAILURE, err, "med_tf: broadcast to race_var failed");      
>+      err = pthread_mutex_unlock (&race_mut);
>+      if (err != 0)
>+        error (EXIT_FAILURE, err, "med_tf: failed to unlock race_mut");      
>+
>+      test_result = 1;
>+    }
>+
>   puts ("med_tf: done spinning");
> 
>   return NULL;
>@@ -159,6 +205,7 @@ do_test (void)
>   pthread_t low_thread;
>   pthread_t med_thread;
>   pthread_t high_thread;
>+  pthread_t watchdog_thread;
>   struct sched_param param;
>   pthread_attr_t attr;
>   pthread_mutexattr_t m_attr;
>@@ -168,7 +215,10 @@ do_test (void)
>   int err;
> 
> 
>-  /* Initialize mutexes and condvars.  */
>+  /* Initialize barrier, mutexes, and condvars.  */
>+  err = pthread_barrier_init (&bar, NULL, 2);
>+  if (err != 0)
>+    error (EXIT_FAILURE, err, "parent: failed to init barrier");
> 
>   err = pthread_attr_init (&attr);
>   if (err != 0)
>@@ -232,6 +282,10 @@ do_test (void)
>   if (err != 0)
>     error (EXIT_FAILURE, err, "parent: failed to set CPU affinity");
> 
>+  err = pthread_create (&watchdog_thread, &attr, watchdog_tf, (void*)NULL);
>+  if (err != 0)
>+    error (EXIT_FAILURE, err, "parent: failed to create watchdog_tf");
>+
>   param.sched_priority = LOW_PRIO;
>   err = pthread_attr_setschedparam (&attr, &param);
>   if (err != 0)
>@@ -266,11 +320,18 @@ do_test (void)
>      PTHREAD_PRIO_INHERIT, low_tf will not have released the race_var cond_lock
>      and neither thread will have waited on race_var.  */
>   usleep (1000);
>+
>+  err = pthread_barrier_wait (&bar);
>+  if (err != 0 && err != PTHREAD_BARRIER_SERIAL_THREAD)
>+    error (EXIT_FAILURE, err, "parent: barrier wait failed");
>   err = pthread_cond_broadcast (&race_var);
>   if (err != 0)
>     error (EXIT_FAILURE, err, "parent: failed to broadcast condition");
> 
>   /* Wait for threads to complete.  */
>+  err = pthread_join (watchdog_thread, (void**) NULL);
>+  if (err != 0)
>+    error (EXIT_FAILURE, err, "join of watchdog_tf failed");
>   err = pthread_join (low_thread, (void**) NULL);
>   if (err != 0)
>     error (EXIT_FAILURE, err, "join of low_tf failed");
>@@ -283,7 +344,7 @@ do_test (void)
> 
>   puts ("done");
> 
>-  return 0;
>+  return test_result;
> }
> 
> 
>-- 
>1.7.0.4
>

Actions: View | Diff

Attachments on bug 11588: 4779 | 4780 | 4781 | 4782 | 4785 | 4786 | 4787 | 4788 | 4789 | 4821 | 7238 | 7239 | 7240 | 7282 | 7442 | 7684 | 7685 | 7686 | 7687 | 7688 | 7689