On Fri, 17 Apr 2026 20:20:00 +0800
Pengpeng Hou <[email protected]> wrote:
> @ -2962,14 +2963,22 @@ find_synthetic_field_var(struct hist_trigger_data
> *target_hist_data,
> char *system, char *event_name, char *field_name)
> {
> struct hist_field *event_var;
> + struct seq_buf s;
> char *synthetic_name;
>
> synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
> if (!synthetic_name)
> return ERR_PTR(-ENOMEM);
>
> - strcpy(synthetic_name, "synthetic_");
> - strcat(synthetic_name, field_name);
> + seq_buf_init(&s, synthetic_name, MAX_FILTER_STR_VAL);
> + seq_buf_puts(&s, "synthetic_");
> + seq_buf_puts(&s, field_name);
newline
> + /* Terminate synthetic_name with a NUL. */
> + seq_buf_str(&s);
newline
> + if (seq_buf_has_overflowed(&s)) {
> + kfree(synthetic_name);
> + return ERR_PTR(-E2BIG);
> + }
>
> event_var = find_event_var(target_hist_data, system, event_name,
> synthetic_name);
>
> @@ -3014,7 +3023,7 @@ create_field_var_hist(struct hist_trigger_data
> *target_hist_data,
> struct trace_event_file *file;
> struct hist_field *key_field;
> struct hist_field *event_var;
> - char *saved_filter;
> + struct seq_buf s;
> char *cmd;
> int ret;
>
> @@ -3059,28 +3068,35 @@ create_field_var_hist(struct hist_trigger_data
> *target_hist_data,
> return ERR_PTR(-ENOMEM);
> }
>
> + seq_buf_init(&s, cmd, MAX_FILTER_STR_VAL);
> +
> /* Use the same keys as the compatible histogram */
> - strcat(cmd, "keys=");
> + seq_buf_puts(&s, "keys=");
>
> for_each_hist_key_field(i, hist_data) {
> key_field = hist_data->fields[i];
> if (!first)
> - strcat(cmd, ",");
> - strcat(cmd, key_field->field->name);
> + seq_buf_putc(&s, ',');
> + seq_buf_puts(&s, key_field->field->name);
> first = false;
> }
>
> /* Create the synthetic field variable specification */
> - strcat(cmd, ":synthetic_");
> - strcat(cmd, field_name);
> - strcat(cmd, "=");
> - strcat(cmd, field_name);
> + seq_buf_printf(&s, ":synthetic_%s=%s", field_name, field_name);
>
> /* Use the same filter as the compatible histogram */
> - saved_filter = find_trigger_filter(hist_data, file);
> - if (saved_filter) {
> - strcat(cmd, " if ");
> - strcat(cmd, saved_filter);
> + {
> + char *saved_filter = find_trigger_filter(hist_data, file);
> +
> + if (saved_filter)
> + seq_buf_printf(&s, " if %s", saved_filter);
> + }
> +
Different function. Should have the comment about adding nul here too.
> + seq_buf_str(&s);
newline
> + if (seq_buf_has_overflowed(&s)) {
> + kfree(cmd);
> + kfree(var_hist);
> + return ERR_PTR(-E2BIG);
> }
-- Steve
