diff options
| -rw-r--r-- | kernel/lockdep.c | 89 |
1 files changed, 37 insertions, 52 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index ce6d09e65ad..5609d309d56 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -985,12 +985,7 @@ static inline int __bfs_backward(struct lock_list *src_entry, * Recursive, forwards-direction lock-dependency checking, used for * both noncyclic checking and for hardirq-unsafe/softirq-unsafe * checking. - * - * (to keep the stackframe of the recursive functions small we - * use these global variables, and we also mark various helper - * functions as noinline.) */ -static struct held_lock *check_source, *check_target; /* * Print a dependency chain entry (this is only done when a deadlock @@ -1014,7 +1009,9 @@ print_circular_bug_entry(struct lock_list *target, unsigned int depth) * header first: */ static noinline int -print_circular_bug_header(struct lock_list *entry, unsigned int depth) +print_circular_bug_header(struct lock_list *entry, unsigned int depth, + struct held_lock *check_src, + struct held_lock *check_tgt) { struct task_struct *curr = current; @@ -1027,9 +1024,9 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth) printk( "-------------------------------------------------------\n"); printk("%s/%d is trying to acquire lock:\n", curr->comm, task_pid_nr(curr)); - print_lock(check_source); + print_lock(check_src); printk("\nbut task is already holding lock:\n"); - print_lock(check_target); + print_lock(check_tgt); printk("\nwhich lock already depends on the new lock.\n\n"); printk("\nthe existing dependency chain (in reverse order) is:\n"); @@ -1043,36 +1040,24 @@ static inline int class_equal(struct lock_list *entry, void *data) return entry->class == data; } -static noinline int print_circular_bug(void) +static noinline int print_circular_bug(struct lock_list *this, + struct lock_list *target, + struct held_lock *check_src, + struct held_lock *check_tgt) { struct task_struct *curr = current; - struct lock_list this; - struct lock_list *target; struct lock_list *parent; - int result; unsigned long depth; if (!debug_locks_off_graph_unlock() || debug_locks_silent) return 0; - this.class = hlock_class(check_source); - this.parent = NULL; - if (!save_trace(&this.trace)) + if (!save_trace(&this->trace)) return 0; - result = __bfs_forward(&this, - hlock_class(check_target), - class_equal, - &target); - if (result) { - printk("\n%s:search shortest path failed:%d\n", __func__, - result); - return 0; - } - depth = get_lock_depth(target); - print_circular_bug_header(target, depth); + print_circular_bug_header(target, depth, check_src, check_tgt); parent = get_lock_parent(target); @@ -1090,6 +1075,16 @@ static noinline int print_circular_bug(void) return 0; } +static noinline int print_bfs_bug(int ret) +{ + if (!debug_locks_off_graph_unlock()) + return 0; + + WARN(1, "lockdep bfs error:%d\n", ret); + + return 0; +} + #define RECURSION_LIMIT 40 static int noinline print_infinite_recursion_bug(void) @@ -1168,31 +1163,17 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class) * lead to <target>. Print an error and return 0 if it does. */ static noinline int -check_noncircular(struct lock_class *source, unsigned int depth) +check_noncircular(struct lock_list *root, struct lock_class *target, + struct lock_list **target_entry) { - struct lock_list *entry; + int result; - if (lockdep_dependency_visit(source, depth)) - return 1; + debug_atomic_inc(&nr_cyclic_checks); - debug_atomic_inc(&nr_cyclic_check_recursions); - if (depth > max_recursion_depth) - max_recursion_depth = depth; - if (depth >= RECURSION_LIMIT) - return print_infinite_recursion_bug(); - /* - * Check this lock's dependency list: - */ - list_for_each_entry(entry, &source->locks_after, entry) { - if (entry->class == hlock_class(check_target)) - return 2; - debug_atomic_inc(&nr_cyclic_checks); - if (check_noncircular(entry->class, depth+1) == 2) - return 2; - } - return 1; -} + result = __bfs_forward(root, target, class_equal, target_entry); + return result; +} #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) /* @@ -1586,6 +1567,8 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, { struct lock_list *entry; int ret; + struct lock_list this; + struct lock_list *uninitialized_var(target_entry); /* * Prove that the new <prev> -> <next> dependency would not @@ -1596,11 +1579,13 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, * We are using global variables to control the recursion, to * keep the stackframe size of the recursive functions low: */ - check_source = next; - check_target = prev; - - if (check_noncircular(hlock_class(next), 0) == 2) - return print_circular_bug(); + this.class = hlock_class(next); + this.parent = NULL; + ret = check_noncircular(&this, hlock_class(prev), &target_entry); + if (unlikely(!ret)) + return print_circular_bug(&this, target_entry, next, prev); + else if (unlikely(ret < 0)) + return print_bfs_bug(ret); if (!check_prev_add_irq(curr, prev, next)) return 0; |