From nobody Wed Apr 8 11:43:14 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E896C25B08 for ; Sat, 20 Aug 2022 13:44:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347614AbiHTNoK (ORCPT ); Sat, 20 Aug 2022 09:44:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346959AbiHTNny (ORCPT ); Sat, 20 Aug 2022 09:43:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52C9824F04; Sat, 20 Aug 2022 06:43:50 -0700 (PDT) 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 6996CB80CE0; Sat, 20 Aug 2022 13:43:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 099B9C43147; Sat, 20 Aug 2022 13:43:47 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.96) (envelope-from ) id 1oPOld-005AMx-0O; Sat, 20 Aug 2022 09:44:01 -0400 Message-ID: <20220820134400.959640191@goodmis.org> User-Agent: quilt/0.66 Date: Sat, 20 Aug 2022 09:43:19 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Masami Hiramatsu , Tzvetomir Stoyanov , Tom Zanussi , stable@vger.kernel.org Subject: [PATCH v2 3/6] tracing/eprobes: Fix reading of string fields References: <20220820134316.156058831@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Steven Rostedt (Google)" Currently when an event probe (eprobe) hooks to a string field, it does not display it as a string, but instead as a number. This makes the field rather useless. Handle the different kinds of strings, dynamic, static, relational/dynamic etc. Now when a string field is used, the ":string" type can be used to display it: echo "e:sw sched/sched_switch comm=3D$next_comm:string" > dynamic_events Cc: stable@vger.kernel.org Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_eprobe.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 550671985fd1..a1d3423ab74f 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -311,6 +311,27 @@ static unsigned long get_event_field(struct fetch_insn= *code, void *rec) =20 addr =3D rec + field->offset; =20 + if (is_string_field(field)) { + switch (field->filter_type) { + case FILTER_DYN_STRING: + val =3D (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); + break; + case FILTER_RDYN_STRING: + val =3D (unsigned long)(addr + (*(unsigned int *)addr & 0xffff)); + break; + case FILTER_STATIC_STRING: + val =3D (unsigned long)addr; + break; + case FILTER_PTR_STRING: + val =3D (unsigned long)(*(char *)addr); + break; + default: + WARN_ON_ONCE(1); + return 0; + } + return val; + } + switch (field->size) { case 1: if (field->is_signed) --=20 2.35.1