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List:       linux-stable-commits
Subject:    patch lockdep-fix-mismatched-lockdep_depth-curr_chain_hash.patch queued to -stable tree
From:       <gregkh () suse ! de>
Date:       2007-10-31 15:45:44
Message-ID: 20071031154610.394DA14540D4 () imap ! suse ! de
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This is a note to let you know that we have just queued up the patch titled

     Subject: [PATCH] lockdep: fix mismatched lockdep_depth/curr_chain_hash

to the 2.6.23-stable tree.  Its filename is

     lockdep-fix-mismatched-lockdep_depth-curr_chain_hash.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


From 3aa416b07f0adf01c090baab26fb70c35ec17623 Mon Sep 17 00:00:00 2001
From: Gregory Haskins <ghaskins@novell.com>
Date: Thu, 11 Oct 2007 22:11:11 +0200
Subject: [PATCH] lockdep: fix mismatched lockdep_depth/curr_chain_hash
 It is possible for the current->curr_chain_key to become inconsistent with the
 current index if the chain fails to validate.  The end result is that future
 lock_acquire() operations may inadvertently fail to find a hit in the cache
 resulting in a new node being added to the graph for every acquire.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 kernel/lockdep.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -1521,7 +1521,7 @@ cache_hit:
 }
 
 static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
-	       	struct held_lock *hlock, int chain_head)
+	       	struct held_lock *hlock, int chain_head, u64 chain_key)
 {
 	/*
 	 * Trylock needs to maintain the stack of held locks, but it
@@ -1534,7 +1534,7 @@ static int validate_chain(struct task_st
 	 * graph_lock for us)
 	 */
 	if (!hlock->trylock && (hlock->check == 2) &&
-			lookup_chain_cache(curr->curr_chain_key, hlock->class)) {
+			lookup_chain_cache(chain_key, hlock->class)) {
 		/*
 		 * Check whether last held lock:
 		 *
@@ -1576,7 +1576,7 @@ static int validate_chain(struct task_st
 #else
 static inline int validate_chain(struct task_struct *curr,
 	       	struct lockdep_map *lock, struct held_lock *hlock,
-		int chain_head)
+		int chain_head, u64 chain_key)
 {
 	return 1;
 }
@@ -2450,11 +2450,11 @@ static int __lock_acquire(struct lockdep
 		chain_head = 1;
 	}
 	chain_key = iterate_chain_key(chain_key, id);
-	curr->curr_chain_key = chain_key;
 
-	if (!validate_chain(curr, lock, hlock, chain_head))
+	if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
 		return 0;
 
+	curr->curr_chain_key = chain_key;
 	curr->lockdep_depth++;
 	check_chain_key(curr);
 #ifdef CONFIG_DEBUG_LOCKDEP


Patches currently in stable-queue which might be from ghaskins@novell.com are

queue-2.6.23/lockdep-fix-mismatched-lockdep_depth-curr_chain_hash.patch
-
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