diff options
| -rw-r--r-- | kernel/trace/trace_events.c | 62 |
1 files changed, 61 insertions, 1 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index ae9a3b8481f5..0d91152172c9 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -40,6 +40,14 @@ static LIST_HEAD(ftrace_generic_fields); static LIST_HEAD(ftrace_common_fields); static bool eventdir_initialized; +static LIST_HEAD(module_strings); + +struct module_string { + struct list_head next; + struct module *module; + char *str; +}; + #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO) static struct kmem_cache *field_cachep; @@ -2633,14 +2641,40 @@ static void update_event_printk(struct trace_event_call *call, } } +static void add_str_to_module(struct module *module, char *str) +{ + struct module_string *modstr; + + modstr = kmalloc(sizeof(*modstr), GFP_KERNEL); + + /* + * If we failed to allocate memory here, then we'll just + * let the str memory leak when the module is removed. + * If this fails to allocate, there's worse problems than + * a leaked string on module removal. + */ + if (WARN_ON_ONCE(!modstr)) + return; + + modstr->module = module; + modstr->str = str; + + list_add(&modstr->next, &module_strings); +} + static void update_event_fields(struct trace_event_call *call, struct trace_eval_map *map) { struct ftrace_event_field *field; struct list_head *head; char *ptr; + char *str; int len = strlen(map->eval_string); + /* Dynamic events should never have field maps */ + if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC)) + return; + head = trace_get_fields(call); list_for_each_entry(field, head, link) { ptr = strchr(field->type, '['); @@ -2654,9 +2688,26 @@ static void update_event_fields(struct trace_event_call *call, if (strncmp(map->eval_string, ptr, len) != 0) continue; + str = kstrdup(field->type, GFP_KERNEL); + if (WARN_ON_ONCE(!str)) + return; + ptr = str + (ptr - field->type); ptr = eval_replace(ptr, map, len); /* enum/sizeof string smaller than value */ - WARN_ON_ONCE(!ptr); + if (WARN_ON_ONCE(!ptr)) { + kfree(str); + continue; + } + + /* + * If the event is part of a module, then we need to free the string + * when the module is removed. Otherwise, it will stay allocated + * until a reboot. + */ + if (call->module) + add_str_to_module(call->module, str); + + field->type = str; } } @@ -2883,6 +2934,7 @@ static void trace_module_add_events(struct module *mod) static void trace_module_remove_events(struct module *mod) { struct trace_event_call *call, *p; + struct module_string *modstr, *m; down_write(&trace_event_sem); list_for_each_entry_safe(call, p, &ftrace_events, list) { @@ -2891,6 +2943,14 @@ static void trace_module_remove_events(struct module *mod) if (call->module == mod) __trace_remove_event_call(call); } + /* Check for any strings allocade for this module */ + list_for_each_entry_safe(modstr, m, &module_strings, next) { + if (modstr->module != mod) + continue; + list_del(&modstr->next); + kfree(modstr->str); + kfree(modstr); + } up_write(&trace_event_sem); /* |