diff options
Diffstat (limited to 'kernel/locking/lockdep.c')
| -rw-r--r-- | kernel/locking/lockdep.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 986f2fa79dbb..b2dd313951ce 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1307,6 +1307,19 @@ check_noncircular(struct lock_list *root, struct lock_class *target, return result; } +static noinline int +check_redundant(struct lock_list *root, struct lock_class *target, + struct lock_list **target_entry) +{ + int result; + + debug_atomic_inc(nr_redundant_checks); + + result = __bfs_forwards(root, target, class_equal, target_entry); + + return result; +} + #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) /* * Forwards and backwards subgraph searching, for the purposes of @@ -1872,6 +1885,20 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, } } + /* + * Is the <prev> -> <next> link redundant? + */ + this.class = hlock_class(prev); + this.parent = NULL; + ret = check_redundant(&this, hlock_class(next), &target_entry); + if (!ret) { + debug_atomic_inc(nr_redundant); + return 2; + } + if (ret < 0) + return print_bfs_bug(ret); + + if (!*stack_saved) { if (!save_trace(&trace)) return 0; |