Re: [PATCH v14 06/15] tracing: Add hist trigger snapshot() action
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2019-02-13 19:25:57
Also in:
lkml
On Tue, 5 Feb 2019 16:41:52 -0600 Tom Zanussi [off-list ref] wrote:
+static struct track_data *track_data_alloc(unsigned int key_len,
+ struct action_data *action_data,
+ struct hist_trigger_data *hist_data)
+{
+ struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
+ unsigned int size = TASK_COMM_LEN;Why have the variable "size"?
+ struct hist_elt_data *elt_data;
+
+ if (!data)
+ return ERR_PTR(-ENOMEM);
+
+ data->key = kzalloc(key_len, GFP_KERNEL);
+ if (!data->key) {
+ track_data_free(data);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ data->key_len = key_len;
+ data->action_data = action_data;
+ data->hist_data = hist_data;
+
+ elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
+ if (!elt_data) {
+ track_data_free(data);
+ return ERR_PTR(-ENOMEM);
+ }
+ data->elt.private_data = elt_data;
+
+ elt_data->comm = kzalloc(size, GFP_KERNEL);Why not just do: elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL); ?
quoted hunk ↗ jump to hunk
+ if (!elt_data->comm) { + track_data_free(data); + return ERR_PTR(-ENOMEM); + } + + return data; +} + static char last_hist_cmd[MAX_FILTER_STR_VAL]; static char hist_err_str[MAX_FILTER_STR_VAL];@@ -1726,12 +1805,6 @@ static struct hist_field *find_event_var(struct hist_trigger_data *hist_data, return hist_field; } -struct hist_elt_data { - char *comm; - u64 *var_ref_vals; - char *field_var_str[SYNTH_FIELDS_MAX]; -}; - static u64 hist_field_var_ref(struct hist_field *hist_field, struct tracing_map_elt *elt, struct ring_buffer_event *rbe,@@ -3452,6 +3525,112 @@ static bool check_track_val(struct tracing_map_elt *elt, return data->track_data.check_val(track_val, var_val); } +#ifdef CONFIG_TRACER_SNAPSHOT +static bool cond_snapshot_update(struct trace_array *tr, void *cond_data) +{ + /* called with tr->max_lock held */ + struct track_data *track_data = tr->cond_snapshot->cond_data; + struct hist_elt_data *elt_data, *track_elt_data; + struct snapshot_context *context = cond_data; + u64 track_val; + + if (!track_data) + return false; + + track_val = get_track_val(track_data->hist_data, context->elt, + track_data->action_data); + + track_data->track_val = track_val; + memcpy(track_data->key, context->key, track_data->key_len); + + elt_data = context->elt->private_data; + track_elt_data = track_data->elt.private_data; + if (elt_data->comm) + memcpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
I noticed this because we hardcode the size in memcpy. Should hard code it above, otherwise it looks like elt_data->comm may be something other than TASK_COMM_LEN. -- Steve
+ + track_data->updated = true; + + return true; +} +