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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D8F5C25B08 for ; Sat, 20 Aug 2022 12:27:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346337AbiHTM1u (ORCPT ); Sat, 20 Aug 2022 08:27:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344848AbiHTM1r (ORCPT ); Sat, 20 Aug 2022 08:27:47 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6FB76543E8; Sat, 20 Aug 2022 05:27:46 -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 sin.source.kernel.org (Postfix) with ESMTPS id DBD27CE0E05; Sat, 20 Aug 2022 12:27:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ACD14C433C1; Sat, 20 Aug 2022 12:27:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660998463; bh=assOHwgQdKBmJy5Y6XWkbZif7DaKqia6uNgtfAA8UVY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bMyKVb/N/JIQ9vcxfpfpLb0jkYMa6dvUqniv0ut1x7pN/QbxuNJTfrOu6AzWIFKz6 NtATJmFiUQ8ikRvezwCgb42wepJQIG/cIle1ET4M7cMuUmUyngai/vEoGLWNjG9nEF Id+Xw+wOSz+eySeyYxSSsl1B4hSMxsHScapy6tR2Wx5LGqsGeTfnsvYIBwNpnGlmR7 8u1aA8Lu9zzmCUtTK9fJbowd1xdup7NGfig1nEn5NcXGUkA6A/Nix0nxhfd/NRVx0y NpfzIj/lPb3PBafsX7tN3g9CeeYIjKr1qxZ2DZqli6Z3e318n1ULuQzNR3kvmy3Ttx AzX0yVCtF70Lg== Date: Sat, 20 Aug 2022 21:27:33 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Masami Hiramatsu , Tzvetomir Stoyanov , Tom Zanussi , stable@vger.kernel.org Subject: Re: [PATCH 3/4] tracing/eprobes: Fix reading of string fields Message-Id: <20220820212733.f19ae9f07c0868af3a008077@kernel.org> In-Reply-To: <20220820014833.220833221@goodmis.org> References: <20220820014035.531145719@goodmis.org> <20220820014833.220833221@goodmis.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 19 Aug 2022 21:40:38 -0400 Steven Rostedt wrote: > 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=$next_comm:string" > dynamic_events Really nice! Acked-by: Masami Hiramatsu (Google) Thank you! > > Cc: stable@vger.kernel.org > Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") > 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) > > addr = rec + field->offset; > > + if (is_string_field(field)) { > + switch (field->filter_type) { > + case FILTER_DYN_STRING: > + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); > + break; > + case FILTER_RDYN_STRING: > + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff)); > + break; > + case FILTER_STATIC_STRING: > + val = (unsigned long)addr; > + break; > + case FILTER_PTR_STRING: > + val = (unsigned long)(*(char *)addr); > + break; > + default: > + WARN_ON_ONCE(1); > + return 0; > + } > + return val; > + } > + > switch (field->size) { > case 1: > if (field->is_signed) > -- > 2.35.1 -- Masami Hiramatsu (Google)