From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDF8FC4363C for ; Sun, 4 Oct 2020 22:14:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B10CC207E8 for ; Sun, 4 Oct 2020 22:14:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601849663; bh=B+dFFMWcp40PJg650sB48Fs22vUJWnZ5MwrtEeFsO3E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=X0FcMeid8ZQTyetqhi2DCUx4G07TXLtfw4qLifvqOrXkSLOpkdNYNWN6lvCksaS9u p6WwNO1NSVzlmK8QD6ttoSFAdR1vWOjYmr3xEdKA+IWNlAozhE6jhBBdeT9jP7UOvx yu3+G8DgadIC+q+f9DCw2n7D0WXsdhKV/J23RXnE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726771AbgJDWOW (ORCPT ); Sun, 4 Oct 2020 18:14:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:59112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726696AbgJDWOR (ORCPT ); Sun, 4 Oct 2020 18:14:17 -0400 Received: from tzanussi-mobl.hsd1.il.comcast.net (c-73-209-127-30.hsd1.il.comcast.net [73.209.127.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CFFE42078A; Sun, 4 Oct 2020 22:14:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601849656; bh=B+dFFMWcp40PJg650sB48Fs22vUJWnZ5MwrtEeFsO3E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=dy2eIyIj4/f8P0oiMXAxLI3QJ6DEkEsGO36T6pQ7ydonKbzbY63euubfJCoVX9MQm UjzwRV0PnBy+MZLvAz1os5iXL1k0kb04zB4S69Iee0TQC2nF6qULN2d7nnKNpuwpsn nMT/xnU07yvNSnrKRyBOpYRe/V9Q92PeaO8miRpI= From: Tom Zanussi To: rostedt@goodmis.org, axelrasmussen@google.com Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 3/7] tracing: Save normal string variables Date: Sun, 4 Oct 2020 17:14:05 -0500 Message-Id: <1c1a03798b02e67307412a0c719d1bfb69b13007.1601848695.git.zanussi@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org String variables created as field variables and save variables are already handled properly by having their values copied when set. The same isn't done for normal variables, but needs to be - simply saving a pointer to a string contained in an old event isn't sufficient, since that event's data may quickly become overwritten and therefore a string pointer to it could yield garbage. This change uses the same mechanism as field variables and simply appends the new strings to the existing per-element field_var_str[] array allocated for that purpose. Fixes: 02205a6752f2 (tracing: Add support for 'field variables') Signed-off-by: Tom Zanussi --- kernel/trace/trace_events_hist.c | 34 ++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 3b22e2122d1a..812bc5f94b5c 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -147,6 +147,8 @@ struct hist_field { */ unsigned int var_ref_idx; bool read_once; + + unsigned int var_str_idx; }; static u64 hist_field_none(struct hist_field *field, @@ -349,6 +351,7 @@ struct hist_trigger_data { unsigned int n_keys; unsigned int n_fields; unsigned int n_vars; + unsigned int n_var_str; unsigned int key_size; struct tracing_map_sort_key sort_keys[TRACING_MAP_SORT_KEYS_MAX]; unsigned int n_sort_keys; @@ -1396,7 +1399,12 @@ static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt) } } - n_str = hist_data->n_field_var_str + hist_data->n_save_var_str; + n_str = hist_data->n_field_var_str + hist_data->n_save_var_str + + hist_data->n_var_str; + if (n_str > SYNTH_FIELDS_MAX) { + hist_elt_data_free(elt_data); + return -EINVAL; + } BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1)); @@ -3653,6 +3661,7 @@ static int create_var_field(struct hist_trigger_data *hist_data, { struct trace_array *tr = hist_data->event_file->tr; unsigned long flags = 0; + int ret; if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX)) return -EINVAL; @@ -3667,7 +3676,12 @@ static int create_var_field(struct hist_trigger_data *hist_data, if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX)) return -EINVAL; - return __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags); + ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags); + + if (hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING) + hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++; + + return ret; } static int create_val_fields(struct hist_trigger_data *hist_data, @@ -4394,6 +4408,22 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data, hist_val = hist_field->fn(hist_field, elt, rbe, rec); if (hist_field->flags & HIST_FIELD_FL_VAR) { var_idx = hist_field->var.idx; + + if (hist_field->flags & HIST_FIELD_FL_STRING) { + unsigned int str_start, var_str_idx, idx; + char *str, *val_str; + + str_start = hist_data->n_field_var_str + + hist_data->n_save_var_str; + var_str_idx = hist_field->var_str_idx; + idx = str_start + var_str_idx; + + str = elt_data->field_var_str[idx]; + val_str = (char *)(uintptr_t)hist_val; + strscpy(str, val_str, STR_VAR_LEN_MAX); + + hist_val = (u64)(uintptr_t)str; + } tracing_map_set_var(elt, var_idx, hist_val); continue; } -- 2.17.1