lkml.org 
[lkml]   [2007]   [Oct]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 27/26] lockdep: fix mismatched lockdep_depth/curr_chain_hash
[one more patch added to the 2.6.22-stable queue]


From: Gregory Haskins <ghaskins@novell.com>

patch 3aa416b07f0adf01c090baab26fb70c35ec17623 in mainline.

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.

[ peterz: this might explain some of the lockdep is so _slow_ complaints. ]
[ mingo: this does not impact the correctness of validation, but may slow
down future operations significantly, if the chain gets very long. ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2166,7 +2166,6 @@ out_calc_hash:
}
#endif
chain_key = iterate_chain_key(chain_key, id);
- curr->curr_chain_key = chain_key;

/*
* Trylock needs to maintain the stack of held locks, but it
@@ -2215,6 +2214,7 @@ out_calc_hash:
if (unlikely(!debug_locks))
return 0;

+ curr->curr_chain_key = chain_key;
curr->lockdep_depth++;
check_chain_key(curr);
#ifdef CONFIG_DEBUG_LOCKDEP
_______________________________________________
stable mailing list
stable@linux.kernel.org
http://linux.kernel.org/mailman/listinfo/stable
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-31 18:07    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site