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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 9306FC54FCB for ; Sat, 25 Apr 2020 14:00:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61CE120714 for ; Sat, 25 Apr 2020 14:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726112AbgDYOAX (ORCPT ); Sat, 25 Apr 2020 10:00:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:36782 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726050AbgDYOAX (ORCPT ); Sat, 25 Apr 2020 10:00:23 -0400 Received: from oasis.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 9575820714; Sat, 25 Apr 2020 14:00:22 +0000 (UTC) Date: Sat, 25 Apr 2020 10:00:20 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: Tom Zanussi , linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: [PATCH 2/3] tracing/boottime: Fix kprobe event API usage Message-ID: <20200425100020.3ccaa586@oasis.local.home> In-Reply-To: <158779375766.6082.201939936008972838.stgit@devnote2> References: <158779373972.6082.16695832932765258919.stgit@devnote2> <158779375766.6082.201939936008972838.stgit@devnote2> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 25 Apr 2020 14:49:17 +0900 Masami Hiramatsu wrote: > Fix boottime kprobe events to use API correctly for > multiple events. > > For example, when we set a multiprobe kprobe events in > bootconfig like below, > > ftrace.event.kprobes.myevent { > probes = "vfs_read $arg1 $arg2", "vfs_write $arg1 $arg2" > } > > This cause an error; > > trace_boot: Failed to add probe: p:kprobes/myevent (null) vfs_read $arg1 $arg2 vfs_write $arg1 $arg2 > > This shows the 1st argument becomes NULL and multiprobes > are merged to 1 probe. > > Fixes: 29a154810546 ("tracing: Change trace_boot to use kprobe_event interface") > Signed-off-by: Masami Hiramatsu > Cc: stable@vger.kernel.org > --- > kernel/trace/trace_boot.c | 20 ++++++++------------ > 1 file changed, 8 insertions(+), 12 deletions(-) > > diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c > index 06d7feb5255f..9de29bb45a27 100644 > --- a/kernel/trace/trace_boot.c > +++ b/kernel/trace/trace_boot.c > @@ -95,24 +95,20 @@ trace_boot_add_kprobe_event(struct xbc_node *node, const char *event) > struct xbc_node *anode; > char buf[MAX_BUF_LEN]; > const char *val; > - int ret; > + int ret = 0; > > - kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN); > + xbc_node_for_each_array_value(node, "probes", anode, val) { > + kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN); > > - ret = kprobe_event_gen_cmd_start(&cmd, event, NULL); > - if (ret) > - return ret; > + ret = kprobe_event_gen_cmd_start(&cmd, event, val); > + if (ret) > + break; Should we break here? What about just printing an error message and continuing to the next probe. If I start up something with a typo in the first element, I lose all events. But if I have a typo in the last one, I get all but that one. I rather have it just fail on the ones that don't parse properly. -- Steve > > - xbc_node_for_each_array_value(node, "probes", anode, val) { > - ret = kprobe_event_add_field(&cmd, val); > + ret = kprobe_event_gen_cmd_end(&cmd); > if (ret) > - return ret; > + pr_err("Failed to add probe: %s\n", buf); > } > > - ret = kprobe_event_gen_cmd_end(&cmd); > - if (ret) > - pr_err("Failed to add probe: %s\n", buf); > - > return ret; > } > #else