The patch titled
lockdep: fix mismatched lockdep_depth/curr_chain_hash
has been added to the -mm tree. Its filename is
lockdep-fix-mismatched-lockdep_depth-curr_chain_hash.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: lockdep: fix mismatched lockdep_depth/curr_chain_hash
From: Gregory Haskins <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
diff -puN kernel/lockdep.c~lockdep-fix-mismatched-lockdep_depth-curr_chain_hash
kernel/lockdep.c
--- a/kernel/lockdep.c~lockdep-fix-mismatched-lockdep_depth-curr_chain_hash
+++ a/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 -mm which might be from [EMAIL PROTECTED] are
git-kvm.patch
lockdep-fix-mismatched-lockdep_depth-curr_chain_hash.patch
-
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