Fix accessing the __rcu pointer direct_functions with RCU protection.
Unified · Split
| @@ -6617,6 +6617,7 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, b · 6616 unmodified lines | ||
| 6617 | 6617 | .func = ftrace_stub, |
| 6618 | 6618 | .flags = FTRACE_OPS_FL_STUB, |
| 6619 | 6619 | }; |
| 6620 | + struct ftrace_hash *direct_hash; | |
| 6620 | 6621 | struct ftrace_hash *orig_hash; |
| 6621 | 6622 | unsigned long size, i; |
| 6622 | 6623 | int err = -EINVAL; |
| @@ -6627,8 +6628,6 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, b · 4 unmodified lines | ||
| 6627 | 6628 | return -EINVAL; |
| 6628 | 6629 | if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) |
| 6629 | 6630 | return -EINVAL; |
| 6630 | − if (direct_functions == EMPTY_HASH) | |
| 6631 | − return -EINVAL; | |
| 6632 | 6631 | |
| 6633 | 6632 | /* |
| 6634 | 6633 | * We can be called from within ops_func callback with direct_mutex |
| @@ -6636,6 +6635,12 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, b · 1 unmodified line | ||
| 6636 | 6635 | */ |
| 6637 | 6636 | if (do_direct_lock) |
| 6638 | 6637 | mutex_lock(&direct_mutex); |
| 6638 | + else | |
| 6639 | + lockdep_assert_held_once(&direct_mutex); | |
| 6640 | + | |
| 6641 | + direct_hash = rcu_dereference_protected(direct_functions, lockdep_is_held(&direct_mutex)); | |
| 6642 | + if (direct_hash == EMPTY_HASH) | |
| 6643 | + goto unlock; | |
| 6639 | 6644 | |
| 6640 | 6645 | orig_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; |
| 6641 | 6646 | if (!orig_hash) |
| @@ -6667,7 +6672,7 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, b · 25 unmodified lines | ||
| 6667 | 6672 | size = 1 << hash->size_bits; |
| 6668 | 6673 | for (i = 0; i < size; i++) { |
| 6669 | 6674 | hlist_for_each_entry(entry, &hash->buckets[i], hlist) { |
| 6670 | − tmp = __ftrace_lookup_ip(direct_functions, entry->ip); | |
| 6675 | + tmp = __ftrace_lookup_ip(direct_hash, entry->ip); | |
| 6671 | 6676 | if (!tmp) |
| 6672 | 6677 | continue; |
| 6673 | 6678 | tmp->direct = entry->direct; |