Messages in this thread Patch in this message | | | Date | Wed, 31 Oct 2007 09:25:14 -0700 | From | Greg KH <> | Subject | [patch 27/26] lockdep: fix mismatched lockdep_depth/curr_chain_hash |
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[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/
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