Gitweb:     http://git.kernel.org/linus/de87fcc124a5d4a171aa32707b3265608ebda6e7
Commit:     de87fcc124a5d4a171aa32707b3265608ebda6e7
Parent:     b2d0994b1301fc3a6a89e1889578dac9227840e3
Author:     Darren Hart <dvhltc@us.ibm.com>
AuthorDate: Thu Mar 12 00:55:46 2009 -0700
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu Mar 12 11:20:56 2009 +0100

    futex: additional (get|put)_futex_key() fixes
    
    Impact: fix races
    
    futex_requeue and futex_lock_pi still had some bad
    (get|put)_futex_key() usage. This patch adds the missing
    put_futex_keys() and corrects a goto in futex_lock_pi() to avoid
    a double get.
    
    Build and boot tested on a 4 way Intel x86_64 workstation.
    Passes basic pthread_mutex and PI tests out of
    ltp/testcases/realtime.
    
    Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
    Acked-by: Peter Zijlstra <peterz@infradead.org>
    Cc: Rusty Russell <rusty@rustcorp.com.au>
    LKML-Reference: <20090312075545.9856.75152.stgit@Aeon>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/futex.c |   16 +++++++++++-----
 1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index e6a4d72..4000454 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -802,8 +802,10 @@ retry:
 
 		ret = get_user(dummy, uaddr2);
 		if (ret)
-			return ret;
+			goto out_put_keys;
 
+		put_futex_key(fshared, &key2);
+		put_futex_key(fshared, &key1);
 		goto retryfull;
 	}
 
@@ -878,6 +880,9 @@ retry:
 			if (hb1 != hb2)
 				spin_unlock(&hb2->lock);
 
+			put_futex_key(fshared, &key2);
+			put_futex_key(fshared, &key1);
+
 			ret = get_user(curval, uaddr1);
 
 			if (!ret)
@@ -1453,6 +1458,7 @@ retry_locked:
 			 * exit to complete.
 			 */
 			queue_unlock(&q, hb);
+			put_futex_key(fshared, &q.key);
 			cond_resched();
 			goto retry;
 
@@ -1595,13 +1601,12 @@ uaddr_faulted:
 
 	ret = get_user(uval, uaddr);
 	if (!ret)
-		goto retry;
+		goto retry_unlocked;
 
-	if (to)
-		destroy_hrtimer_on_stack(&to->timer);
-	return ret;
+	goto out_put_key;
 }
 
+
 /*
  * Userspace attempted a TID -> 0 atomic transition, and failed.
  * This is the in-kernel slowpath: we look up the PI state (if any),
@@ -1705,6 +1710,7 @@ pi_faulted:
 	}
 
 	ret = get_user(uval, uaddr);
+	put_futex_key(fshared, &key);
 	if (!ret)
 		goto retry;
 
--
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