From patchwork Fri Feb 17 00:49:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 58309 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:eb09:0:0:0:0:0 with SMTP id s9csp617266wrn; Thu, 16 Feb 2023 16:55:26 -0800 (PST) X-Google-Smtp-Source: AK7set/eAiTDTvKnMdBV9yc7wnrjgfHluZ4LSDRh5wWAsyiKbWw1XNRfjv+Aw9hSvlauVwlzwUam X-Received: by 2002:aa7:d351:0:b0:4ad:714e:2372 with SMTP id m17-20020aa7d351000000b004ad714e2372mr2424558edr.14.1676595326014; Thu, 16 Feb 2023 16:55:26 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1676595325; cv=none; d=google.com; s=arc-20160816; b=S7vl32r8YKpes7Elb6iUhekrmy8eoVrljYJVofkkMfkWBWc38iv9p7y12y/fg9oPZZ ycR3x46HT+kC8sZBxhBNvnfaeCLQPYF+1UUs5+UdxnKIF2ftYFDG6tVFHIhCxsIKiSjZ G4jg/eOv8xTpu8bznZ/YXRXTD7p3xUY5VUaZeiunggxRYKNyh+HLNtnWv8c74G5bDYV0 GXfO6YhjUsE/Hsaaub6qSiMjqzB1N0cxPekkichnLjC3H5IkDHIeVn8igVgryBg+XM6R Cy5YR8UwI/GWuACAXv+KucDYCpogqcaSSuWaT/0dZK+wKLJh9FzKO8O4FOw3N7Pc+vUi BrGg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:references:subject:cc:to:from:date :user-agent:message-id; bh=jpSNA1xA/JIC9LjnhBw5wmkybHxZwsYs26ZbLaIDwao=; b=L58BfrslJISklcgsYkZ8fV/0m/LDNd6u9aSZH3tYNyqdW2y0W7U7f8ovwoPRMcHQra StqFbfRbVMIbhHC7bmTvp9GxFxXrNo7OUo/65P5cuBn2r+HFtyByKxIgUAzVkdyH5rrf UCZnaNukxSETLBhuKSwOOFadweRLac+mZjmxlYv9kw4C+g7jAz1sa8h4gDAJSJkyM1a+ L7MwGd587VnGq+kdUqA1+dBBQnVTgtJy2n8jA3F7J1DlZ0rq/p1cMtU31UqCKLFKjRR3 Lodx+Z9CswxQfXRFiwXud7Gcy2MrRZqioUy4JXFJDtpMWdFBcNT3c7Jd8uWJ7NmoA72B m17A== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id f16-20020a056402151000b004aab36d2eb8si3482881edw.62.2023.02.16.16.55.02; Thu, 16 Feb 2023 16:55:25 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229843AbjBQAvB (ORCPT + 99 others); Thu, 16 Feb 2023 19:51:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230157AbjBQAu6 (ORCPT ); Thu, 16 Feb 2023 19:50:58 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9E4C5775C for ; Thu, 16 Feb 2023 16:50:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2F4B0B82ABC for ; Fri, 17 Feb 2023 00:50:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6733C433EF; Fri, 17 Feb 2023 00:50:39 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.96) (envelope-from ) id 1pSoxS-000qMe-24; Thu, 16 Feb 2023 19:50:38 -0500 Message-ID: <20230217005038.455296375@goodmis.org> User-Agent: quilt/0.66 Date: Thu, 16 Feb 2023 19:49:55 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Andrew Morton , Tom Zanussi Subject: [for-next][PATCH 1/5] tracing/histogram: Dont use strlen to find length of stacktrace variables References: <20230217004954.719324747@goodmis.org> MIME-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1758037620800888282?= X-GMAIL-MSGID: =?utf-8?q?1758037620800888282?= From: Tom Zanussi Because stacktraces are saved in dynamic strings, trace_event_raw_event_synth() uses strlen to determine the length of the stack. Stacktraces may contain 0-bytes, though, in the saved addresses, so the length found and passed to reserve() will be too small. Fix this by using the first unsigned long in the stack variables to store the actual number of elements in the stack and have trace_event_raw_event_synth() use that to determine the length of the stack. Link: https://lkml.kernel.org/r/1ed6906cd9d6477ef2bd8e63c61de20a9ffe64d7.1676063532.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_hist.c | 12 ++++++++---- kernel/trace/trace_events_synth.c | 7 ++++++- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 7f3e6ca6f0fa..f21e42ddba69 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -3137,13 +3137,15 @@ static inline void __update_field_vars(struct tracing_map_elt *elt, size = min(val->size, STR_VAR_LEN_MAX); strscpy(str, val_str, size); } else { + char *stack_start = str + sizeof(unsigned long); int e; - e = stack_trace_save((void *)str, + e = stack_trace_save((void *)stack_start, HIST_STACKTRACE_DEPTH, HIST_STACKTRACE_SKIP); if (e < HIST_STACKTRACE_DEPTH - 1) - ((unsigned long *)str)[e] = 0; + ((unsigned long *)stack_start)[e] = 0; + *((unsigned long *)str) = e; } var_val = (u64)(uintptr_t)str; } @@ -5135,13 +5137,15 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data, size = min(hist_field->size, STR_VAR_LEN_MAX); strscpy(str, val_str, size); } else { + char *stack_start = str + sizeof(unsigned long); int e; - e = stack_trace_save((void *)str, + e = stack_trace_save((void *)stack_start, HIST_STACKTRACE_DEPTH, HIST_STACKTRACE_SKIP); if (e < HIST_STACKTRACE_DEPTH - 1) - ((unsigned long *)str)[e] = 0; + ((unsigned long *)stack_start)[e] = 0; + *((unsigned long *)str) = e; } hist_val = (u64)(uintptr_t)str; } diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 306c89e0ce55..70bddb25d9c0 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -538,7 +538,12 @@ static notrace void trace_event_raw_event_synth(void *__data, val_idx = var_ref_idx[field_pos]; str_val = (char *)(long)var_ref_vals[val_idx]; - len = kern_fetch_store_strlen((unsigned long)str_val); + if (event->dynamic_fields[i]->is_stack) { + len = *((unsigned long *)str_val); + len *= sizeof(unsigned long); + } else { + len = kern_fetch_store_strlen((unsigned long)str_val); + } fields_size += len; }