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, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8E74AC433DB for ; Mon, 15 Feb 2021 19:56:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5715364E23 for ; Mon, 15 Feb 2021 19:56:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230407AbhBOT4w (ORCPT ); Mon, 15 Feb 2021 14:56:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:48934 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230090AbhBOT4j (ORCPT ); Mon, 15 Feb 2021 14:56:39 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2E05564E2C; Mon, 15 Feb 2021 19:55:59 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94) (envelope-from ) id 1lBjyQ-0009Tl-48; Mon, 15 Feb 2021 14:55:58 -0500 Message-ID: <20210215195558.014071661@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 15 Feb 2021 14:55:36 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Masami Hiramatsu Subject: [for-next][PATCH 3/5] tracing: Add ptr-hash option to show the hashed pointer value References: <20210215195533.101751000@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masami Hiramatsu Add tracefs/options/hash-ptr option to show hashed pointer value by %p in event printk format string. For the security reason, normal printk will show the hashed pointer value (encrypted by random number) with %p to printk buffer to hide the real address. But the tracefs/trace always shows real address for debug. To bridge those outputs, add an option to switch the output format. Ftrace users can use it to find the hashed value corresponding to the real address in trace log. Link: https://lkml.kernel.org/r/160277372504.29307.14909828808982012211.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- Documentation/trace/ftrace.rst | 6 ++++++ kernel/trace/trace.c | 3 +++ kernel/trace/trace.h | 1 + 3 files changed, 10 insertions(+) diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 87cf5c010d5d..62c98e9bbdd9 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -1159,6 +1159,12 @@ Here are the available options: This simulates the original behavior of the trace file. When the file is closed, tracing will be enabled again. + hash-ptr + When set, "%p" in the event printk format displays the + hashed pointer value instead of real address. + This will be useful if you want to find out which hashed + value is corresponding to the real value in trace log. + record-cmd When any event or tracer is enabled, a hook is enabled in the sched_switch trace point to fill comm cache diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 39f8a537196e..16e252d39016 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3558,6 +3558,9 @@ const char *trace_event_format(struct trace_iterator *iter, const char *fmt) if (WARN_ON_ONCE(!fmt)) return fmt; + if (iter->tr->trace_flags & TRACE_ITER_HASH_PTR) + return fmt; + p = fmt; new_fmt = q = iter->fmt; while (*p) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6c3ea6f95e68..dec13ff66077 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1175,6 +1175,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf, C(MARKERS, "markers"), \ C(EVENT_FORK, "event-fork"), \ C(PAUSE_ON_TRACE, "pause-on-trace"), \ + C(HASH_PTR, "hash-ptr"), /* Print hashed pointer */ \ FUNCTION_FLAGS \ FGRAPH_FLAGS \ STACK_FLAGS \ -- 2.30.0