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Date: Fri, 22 Jun 2007 10:05:00 -0000
From: Jakub Jelinek <jakub@redhat.com>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Glibc hackers <libc-hacker@sources.redhat.com>
Subject: [PATCH] Fix pthread_getattr_np
Message-ID: <20070622100947.GE3081@sunsite.mff.cuni.cz>
Reply-To: Jakub Jelinek <jakub@redhat.com>
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X-SW-Source: 2007-06/txt/msg00018.txt.bz2

Hi!

My reading of pthread_getattr_np is that following code will crash:
pthread_attr_t attr;
memset (&attr, 0xaa, sizeof (attr));  // Stress that attr is uninitialized
if (pthread_getattr_np (pthread_self (), &attr) == 0)
  pthread_attr_destroy (&attr);
if sched_getaffinity returns ENOSYS.
One way to fix this is below, another would be e.g. to clear whole
pthread_attr_t at the start of pthread_getattr_np.  That could cure even
crashes on invalid careless code like e.g. boehm-gc does:
  my_pthread = pthread_self();
  pthread_getattr_np (my_pthread, &attr);
  pthread_attr_getstack (&attr, (void **) &stack_addr, &stack_size);
  pthread_attr_destroy (&attr);
(which has to be fixed anyway).

2007-06-22  Jakub Jelinek  <jakub@redhat.com>

	* pthread_getattr_np.c (pthread_getattr_np): Clear cpuset and
	cpusetsize if pthread_getaffinity_np failed with ENOSYS.

--- libc/nptl/pthread_getattr_np.c.jj	2007-06-04 08:42:05.000000000 +0200
+++ libc/nptl/pthread_getattr_np.c	2007-06-22 11:41:48.000000000 +0200
@@ -164,8 +164,12 @@ pthread_getattr_np (thread_id, attr)
 	{
 	  free (cpuset);
 	  if (ret == ENOSYS)
-	    /* There is no such functionality.  */
-	    ret = 0;
+	    {	  
+	      /* There is no such functionality.  */
+	      ret = 0;
+	      iattr->cpuset = NULL;
+	      iattr->cpusetsize = 0;
+	    }
 	}
     }
 

	Jakub