diff options
| -rw-r--r-- | kernel/locking/lockdep.c | 40 |
1 files changed, 19 insertions, 21 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 7cf02fab1725..841828ba35b9 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1824,20 +1824,13 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, */ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next, int distance, int *stack_saved) + struct held_lock *next, int distance, struct stack_trace *trace, + int (*save)(struct stack_trace *trace)) { struct lock_list *entry; int ret; struct lock_list this; struct lock_list *uninitialized_var(target_entry); - /* - * Static variable, serialized by the graph_lock(). - * - * We use this static variable to save the stack trace in case - * we call into this function multiple times due to encountering - * trylocks in the held lock stack. - */ - static struct stack_trace trace; /* * Prove that the new <prev> -> <next> dependency would not @@ -1899,11 +1892,8 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, return print_bfs_bug(ret); - if (!*stack_saved) { - if (!save_trace(&trace)) - return 0; - *stack_saved = 1; - } + if (save && !save(trace)) + return 0; /* * Ok, all validations passed, add the new lock @@ -1911,14 +1901,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, */ ret = add_lock_to_list(hlock_class(next), &hlock_class(prev)->locks_after, - next->acquire_ip, distance, &trace); + next->acquire_ip, distance, trace); if (!ret) return 0; ret = add_lock_to_list(hlock_class(prev), &hlock_class(next)->locks_before, - next->acquire_ip, distance, &trace); + next->acquire_ip, distance, trace); if (!ret) return 0; @@ -1926,8 +1916,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, * Debugging printouts: */ if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { - /* We drop graph lock, so another thread can overwrite trace. */ - *stack_saved = 0; graph_unlock(); printk("\n new dependency: "); print_lock_name(hlock_class(prev)); @@ -1951,8 +1939,9 @@ static int check_prevs_add(struct task_struct *curr, struct held_lock *next) { int depth = curr->lockdep_depth; - int stack_saved = 0; struct held_lock *hlock; + struct stack_trace trace; + int (*save)(struct stack_trace *trace) = save_trace; /* * Debugging checks. @@ -1977,9 +1966,18 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) * added: */ if (hlock->read != 2 && hlock->check) { - if (!check_prev_add(curr, hlock, next, - distance, &stack_saved)) + int ret = check_prev_add(curr, hlock, next, + distance, &trace, save); + if (!ret) return 0; + + /* + * Stop saving stack_trace if save_trace() was + * called at least once: + */ + if (save && ret == 2) + save = NULL; + /* * Stop after the first non-trylock entry, * as non-trylock entries have added their |