From: Andreas Schwab <schwab@redhat.com>
Date: Fri, 25 Jun 2010 08:41:17 +0000 (+0200)
Subject: Fix setxid race handling exiting threads
X-Git-Tag: glibc-2.14.1~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69c1dfc1a7964cc15d429350905aea821803a40c;p=thirdparty%2Fglibc.git

Fix setxid race handling exiting threads
(cherry picked from commit 523df511514331a7fa0668b37a917b52f71684af)
---

diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index 7411ae5e6fe..c4ae3cb38b0 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-31  Andreas Schwab  <schwab@redhat.com>
+
+	* allocatestack.c (setxid_mark_thread): Ensure that the exiting
+	thread is woken up.
+
 2011-08-08  Andreas Schwab  <schwab@redhat.com>
 
 	* sysdeps/unix/sysv/linux/x86_64/cancellation.S: Maintain aligned
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 82408f5178f..d4364bf218b 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -999,7 +999,16 @@ setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
 
       /* If the thread is exiting right now, ignore it.  */
       if ((ch & EXITING_BITMASK) != 0)
-	return;
+	{
+	  /* Release the futex if there is no other setxid in
+	     progress.  */
+	  if ((ch & SETXID_BITMASK) == 0)
+	    {
+	      t->setxid_futex = 1;
+	      lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE);
+	    }
+	  return;
+	}
     }
   while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
 					       ch | SETXID_BITMASK, ch));