diff options
Diffstat (limited to 'kernel/trace/ftrace.c')
| -rw-r--r-- | kernel/trace/ftrace.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index eca34503f178..356b848c697a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2814,7 +2814,7 @@ int ftrace_shutdown(struct ftrace_ops *ops, int command) * synchornize_rcu_tasks() will wait for those tasks to * execute and either schedule voluntarily or enter user space. */ - if (IS_ENABLED(CONFIG_PREEMPT)) + if (IS_ENABLED(CONFIG_PREEMPTION)) synchronize_rcu_tasks(); free_ops: @@ -3095,6 +3095,14 @@ t_probe_next(struct seq_file *m, loff_t *pos) hnd = &iter->probe_entry->hlist; hash = iter->probe->ops.func_hash->filter_hash; + + /* + * A probe being registered may temporarily have an empty hash + * and it's at the end of the func_probes list. + */ + if (!hash || hash == EMPTY_HASH) + return NULL; + size = 1 << hash->size_bits; retry: @@ -4320,12 +4328,21 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr, mutex_unlock(&ftrace_lock); + /* + * Note, there's a small window here that the func_hash->filter_hash + * may be NULL or empty. Need to be carefule when reading the loop. + */ mutex_lock(&probe->ops.func_hash->regex_lock); orig_hash = &probe->ops.func_hash->filter_hash; old_hash = *orig_hash; hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); + if (!hash) { + ret = -ENOMEM; + goto out; + } + ret = ftrace_match_records(hash, glob, strlen(glob)); /* Nothing found? */ |