diff options
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 251 |
1 files changed, 146 insertions, 105 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 2403ce5b6507..f5d335d28d0b 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -425,10 +425,15 @@ int filter_match_preds(struct event_filter *filter, void *rec) struct filter_pred *preds; struct filter_pred *pred; struct filter_pred *root; - int n_preds = ACCESS_ONCE(filter->n_preds); + int n_preds; int done = 0; /* no filter is considered a match */ + if (!filter) + return 1; + + n_preds = filter->n_preds; + if (!n_preds) return 1; @@ -509,6 +514,9 @@ static void parse_error(struct filter_parse_state *ps, int err, int pos) static void remove_filter_string(struct event_filter *filter) { + if (!filter) + return; + kfree(filter->filter_string); filter->filter_string = NULL; } @@ -568,9 +576,10 @@ static void append_filter_err(struct filter_parse_state *ps, void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s) { - struct event_filter *filter = call->filter; + struct event_filter *filter; mutex_lock(&event_mutex); + filter = call->filter; if (filter && filter->filter_string) trace_seq_printf(s, "%s\n", filter->filter_string); else @@ -581,9 +590,10 @@ void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s) void print_subsystem_event_filter(struct event_subsystem *system, struct trace_seq *s) { - struct event_filter *filter = system->filter; + struct event_filter *filter; mutex_lock(&event_mutex); + filter = system->filter; if (filter && filter->filter_string) trace_seq_printf(s, "%s\n", filter->filter_string); else @@ -745,26 +755,9 @@ static void __free_preds(struct event_filter *filter) filter->n_preds = 0; } -static void reset_preds(struct event_filter *filter) -{ - int n_preds = filter->n_preds; - int i; - - filter->n_preds = 0; - filter->root = NULL; - if (!filter->preds) - return; - - for (i = 0; i < n_preds; i++) - filter->preds[i].fn = filter_pred_none; -} - -static void filter_disable_preds(struct ftrace_event_call *call) +static void filter_disable(struct ftrace_event_call *call) { - struct event_filter *filter = call->filter; - call->flags &= ~TRACE_EVENT_FL_FILTERED; - reset_preds(filter); } static void __free_filter(struct event_filter *filter) @@ -777,11 +770,16 @@ static void __free_filter(struct event_filter *filter) kfree(filter); } +/* + * Called when destroying the ftrace_event_call. + * The call is being freed, so we do not need to worry about + * the call being currently used. This is for module code removing + * the tracepoints from within it. + */ void destroy_preds(struct ftrace_event_call *call) { __free_filter(call->filter); call->filter = NULL; - call->flags &= ~TRACE_EVENT_FL_FILTERED; } static struct event_filter *__alloc_filter(void) @@ -789,11 +787,6 @@ static struct event_filter *__alloc_filter(void) struct event_filter *filter; filter = kzalloc(sizeof(*filter), GFP_KERNEL); - if (!filter) - return ERR_PTR(-ENOMEM); - - filter->n_preds = 0; - return filter; } @@ -838,46 +831,28 @@ static int __alloc_preds(struct event_filter *filter, int n_preds) return 0; } -static int init_filter(struct ftrace_event_call *call) -{ - if (call->filter) - return 0; - - call->flags &= ~TRACE_EVENT_FL_FILTERED; - call->filter = __alloc_filter(); - if (IS_ERR(call->filter)) - return PTR_ERR(call->filter); - - return 0; -} - -static int init_subsystem_preds(struct event_subsystem *system) +static void filter_free_subsystem_preds(struct event_subsystem *system) { struct ftrace_event_call *call; - int err; list_for_each_entry(call, &ftrace_events, list) { if (strcmp(call->class->system, system->name) != 0) continue; - err = init_filter(call); - if (err) - return err; + filter_disable(call); + remove_filter_string(call->filter); } - - return 0; } -static void filter_free_subsystem_preds(struct event_subsystem *system) +static void filter_free_subsystem_filters(struct event_subsystem *system) { struct ftrace_event_call *call; list_for_each_entry(call, &ftrace_events, list) { if (strcmp(call->class->system, system->name) != 0) continue; - - filter_disable_preds(call); - remove_filter_string(call->filter); + __free_filter(call->filter); + call->filter = NULL; } } @@ -1743,88 +1718,129 @@ fail: return err; } +struct filter_list { + struct list_head list; + struct event_filter *filter; +}; + static int replace_system_preds(struct event_subsystem *system, struct filter_parse_state *ps, char *filter_string) { struct ftrace_event_call *call; + struct filter_list *filter_item; + struct filter_list *tmp; + LIST_HEAD(filter_list); bool fail = true; int err; list_for_each_entry(call, &ftrace_events, list) { - struct event_filter *filter = call->filter; if (strcmp(call->class->system, system->name) != 0) continue; - /* try to see if the filter can be applied */ - err = replace_preds(call, filter, ps, filter_string, true); + /* + * Try to see if the filter can be applied + * (filter arg is ignored on dry_run) + */ + err = replace_preds(call, NULL, ps, filter_string, true); if (err) goto fail; } - /* set all filter pred counts to zero */ list_for_each_entry(call, &ftrace_events, list) { - struct event_filter *filter = call->filter; + struct event_filter *filter; if (strcmp(call->class->system, system->name) != 0) continue; - reset_preds(filter); - } + filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL); + if (!filter_item) + goto fail_mem; - /* - * Since some of the preds may be used under preemption - * we need to wait for them to finish before we may - * reallocate them. - */ - synchronize_sched(); + list_add_tail(&filter_item->list, &filter_list); - list_for_each_entry(call, &ftrace_events, list) { - struct event_filter *filter = call->filter; + filter_item->filter = __alloc_filter(); + if (!filter_item->filter) + goto fail_mem; + filter = filter_item->filter; - if (strcmp(call->class->system, system->name) != 0) - continue; + /* Can only fail on no memory */ + err = replace_filter_string(filter, filter_string); + if (err) + goto fail_mem; - /* really apply the filter */ - filter_disable_preds(call); err = replace_preds(call, filter, ps, filter_string, false); - if (err) - filter_disable_preds(call); - else { + if (err) { + filter_disable(call); + parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0); + append_filter_err(ps, filter); + } else call->flags |= TRACE_EVENT_FL_FILTERED; - replace_filter_string(filter, filter_string); - } + /* + * Regardless of if this returned an error, we still + * replace the filter for the call. + */ + filter = call->filter; + call->filter = filter_item->filter; + filter_item->filter = filter; + fail = false; } if (fail) goto fail; + /* + * The calls can still be using the old filters. + * Do a synchronize_sched() to ensure all calls are + * done with them before we free them. + */ + synchronize_sched(); + list_for_each_entry_safe(filter_item, tmp, &filter_list, list) { + __free_filter(filter_item->filter); + list_del(&filter_item->list); + kfree(filter_item); + } return 0; fail: + /* No call succeeded */ + list_for_each_entry_safe(filter_item, tmp, &filter_list, list) { + list_del(&filter_item->list); + kfree(filter_item); + } parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0); return -EINVAL; + fail_mem: + /* If any call succeeded, we still need to sync */ + if (!fail) + synchronize_sched(); + list_for_each_entry_safe(filter_item, tmp, &filter_list, list) { + __free_filter(filter_item->filter); + list_del(&filter_item->list); + kfree(filter_item); + } + return -ENOMEM; } int apply_event_filter(struct ftrace_event_call *call, char *filter_string) { - int err; struct filter_parse_state *ps; + struct event_filter *filter; + struct event_filter *tmp; + int err = 0; mutex_lock(&event_mutex); - err = init_filter(call); - if (err) - goto out_unlock; - if (!strcmp(strstrip(filter_string), "0")) { - filter_disable_preds(call); - reset_preds(call->filter); + filter_disable(call); + filter = call->filter; + if (!filter) + goto out_unlock; + call->filter = NULL; /* Make sure the filter is not being used */ synchronize_sched(); - __free_preds(call->filter); - remove_filter_string(call->filter); + __free_filter(filter); goto out_unlock; } @@ -1833,29 +1849,41 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) if (!ps) goto out_unlock; - filter_disable_preds(call); - replace_filter_string(call->filter, filter_string); + filter = __alloc_filter(); + if (!filter) { + kfree(ps); + goto out_unlock; + } + + replace_filter_string(filter, filter_string); parse_init(ps, filter_ops, filter_string); err = filter_parse(ps); if (err) { - append_filter_err(ps, call->filter); + append_filter_err(ps, filter); goto out; } - /* - * Make sure all the pred counts are zero so that - * no task is using it when we reallocate the preds array. - */ - reset_preds(call->filter); - synchronize_sched(); - - err = replace_preds(call, call->filter, ps, filter_string, false); - if (err) - append_filter_err(ps, call->filter); - else + err = replace_preds(call, filter, ps, filter_string, false); + if (err) { + filter_disable(call); + append_filter_err(ps, filter); + } else call->flags |= TRACE_EVENT_FL_FILTERED; out: + /* + * Always swap the call filter with the new filter + * even if there was an error. If there was an error + * in the filter, we disable the filter and show the error + * string + */ + tmp = call->filter; + call->filter = filter; + if (tmp) { + /* Make sure the call is done with the filter */ + synchronize_sched(); + __free_filter(tmp); + } filter_opstack_clear(ps); postfix_clear(ps); kfree(ps); @@ -1868,18 +1896,21 @@ out_unlock: int apply_subsystem_event_filter(struct event_subsystem *system, char *filter_string) { - int err; struct filter_parse_state *ps; + struct event_filter *filter; + int err = 0; mutex_lock(&event_mutex); - err = init_subsystem_preds(system); - if (err) - goto out_unlock; - if (!strcmp(strstrip(filter_string), "0")) { filter_free_subsystem_preds(system); remove_filter_string(system->filter); + filter = system->filter; + system->filter = NULL; + /* Ensure all filters are no longer used */ + synchronize_sched(); + filter_free_subsystem_filters(system); + __free_filter(filter); goto out_unlock; } @@ -1888,7 +1919,17 @@ int apply_subsystem_event_filter(struct event_subsystem *system, if (!ps) goto out_unlock; - replace_filter_string(system->filter, filter_string); + filter = __alloc_filter(); + if (!filter) + goto out; + + replace_filter_string(filter, filter_string); + /* + * No event actually uses the system filter + * we can free it without synchronize_sched(). + */ + __free_filter(system->filter); + system->filter = filter; parse_init(ps, filter_ops, filter_string); err = filter_parse(ps); @@ -1945,7 +1986,7 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id, goto out_unlock; filter = __alloc_filter(); - if (IS_ERR(filter)) { + if (!filter) { err = PTR_ERR(filter); goto out_unlock; } |