From: Richard Braun <rbraun@sceen.net>
Subject: [PATCH] Hurd: fix port leak in TLS

Depending on whether the thread is the main thread or not, the threading
library can have trouble determining whether the thread reference in the
TCB is valid. The simple solution is to let the threading library
initialize the TCB, and use a temporary reference when initializing TLS.

* sysdeps/mach/hurd/i386/tls.h (_hurd_tls_init): Use a temporary thread
reference.

---
 sysdeps/mach/hurd/i386/tls.h | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

--- a/sysdeps/mach/hurd/i386/tls.h
+++ b/sysdeps/mach/hurd/i386/tls.h
@@ -69,6 +69,8 @@ static inline const char * __attribute__
 _hurd_tls_init (tcbhead_t *tcb, int secondcall)
 {
   HURD_TLS_DESC_DECL (desc, tcb);
+  thread_t self = __mach_thread_self ();
+  const char *msg = NULL;
 
   if (!secondcall)
     {
@@ -76,25 +78,26 @@ _hurd_tls_init (tcbhead_t *tcb, int seco
 	 from the TLS point of view.  */
       tcb->tcb = tcb;
 
-      /* Cache our thread port.  */
-      tcb->self = __mach_thread_self ();
-
       /* Get the first available selector.  */
       int sel = -1;
-      kern_return_t err = __i386_set_gdt (tcb->self, &sel, desc);
+      kern_return_t err = __i386_set_gdt (self, &sel, desc);
       if (err == MIG_BAD_ID)
 	{
 	  /* Old kernel, use a per-thread LDT.  */
 	  sel = 0x27;
-	  err = __i386_set_ldt (tcb->self, sel, &desc, 1);
+	  err = __i386_set_ldt (self, sel, &desc, 1);
 	  assert_perror (err);
 	  if (err)
-	    return "i386_set_ldt failed";
+	    {
+	      msg = "i386_set_ldt failed";
+	      goto out;
+	    }
 	}
       else if (err)
 	{
 	  assert_perror (err); /* Separate from above with different line #. */
-	  return "i386_set_gdt failed";
+	  msg = "i386_set_gdt failed";
+	  goto out;
 	}
 
       /* Now install the new selector.  */
@@ -107,21 +110,29 @@ _hurd_tls_init (tcbhead_t *tcb, int seco
       asm ("mov %%gs, %w0" : "=q" (sel) : "0" (0));
       if (__builtin_expect (sel, 0x48) & 4) /* LDT selector */
 	{
-	  kern_return_t err = __i386_set_ldt (tcb->self, sel, &desc, 1);
+	  kern_return_t err = __i386_set_ldt (self, sel, &desc, 1);
 	  assert_perror (err);
 	  if (err)
-	    return "i386_set_ldt failed";
+	    {
+	      msg = "i386_set_ldt failed";
+	      goto out;
+	    }
 	}
       else
 	{
-	  kern_return_t err = __i386_set_gdt (tcb->self, &sel, desc);
+	  kern_return_t err = __i386_set_gdt (self, &sel, desc);
 	  assert_perror (err);
 	  if (err)
-	    return "i386_set_gdt failed";
+	    {
+	      msg = "i386_set_gdt failed";
+	      goto out;
+	    }
 	}
     }
 
-  return 0;
+out:
+  __mach_port_deallocate (__mach_task_self (), self);
+  return msg;
 }
 
 /* Code to initially initialize the thread pointer.  This might need