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 288F6EB64DC for ; Mon, 3 Jul 2023 08:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229591AbjGCIlV (ORCPT ); Mon, 3 Jul 2023 04:41:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229520AbjGCIlU (ORCPT ); Mon, 3 Jul 2023 04:41:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 163E3B6; Mon, 3 Jul 2023 01:41:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0F7D260DFC; Mon, 3 Jul 2023 08:41:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F9C9C433C8; Mon, 3 Jul 2023 08:41:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688373678; bh=d5tEEoXis+6rNIIz2nfMllrQPz1AqmYDceP1A2JH4Cg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TnlwvVial1YwcI5iiIAKpYUZnDLCAyvnhnQqg3Slu0ti/JklkdeUar2hHbB4ZEvf/ kzhTy9CXSkl2s3q8qcnYhCif3SCjPYwX+Pqs5ZqBGMizJ/xxW8LkpDFqWbdEBqu0F6 c1Mz6BUeF86H/uoGlaLhdBzuvy7pth9eX5jdgl2UosPywmW9EtfygOrrtOCLkncPxK yLbQSJDGaaa/IM3zn6NAYHDZ3N48e660yg+qFIZOo5Pm40yCpo5cZM9QCfJcW1OM8t 2leJqaa4LsVwAqgKUPA5z8e2uPBxmFdVDxunQ/XUYnLToqCx+f9y0rX8SnMfteln2O Z/4zYKhhsapkw== Date: Mon, 3 Jul 2023 17:41:14 +0900 From: Masami Hiramatsu (Google) To: "Tzvetomir Stoyanov (VMware)" Cc: rostedt@goodmis.org, mhiramat@kernel.org, dan.carpenter@linaro.org, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] kernel/trace: Fix cleanup logic of enable_trace_eprobe Message-Id: <20230703174114.dd2a7c53b35ab4c3e25a4366@kernel.org> In-Reply-To: <20230703042853.1427493-1-tz.stoyanov@gmail.com> References: <20230703042853.1427493-1-tz.stoyanov@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; 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-trace-kernel@vger.kernel.org On Mon, 3 Jul 2023 07:28:53 +0300 "Tzvetomir Stoyanov (VMware)" wrote: > The enable_trace_eprobe() function enables all event probes, attached > to given trace probe. If an error occurs in enabling one of the event > probes, all others should be roll backed. There is a bug in that roll > back logic - instead of all event probes, only the failed one is > disabled. This looks good to me. Acked-by: Masami Hiramatsu (Google) Thank you, > > Reported-by: Dan Carpenter > Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") > Signed-off-by: Tzvetomir Stoyanov (VMware) > --- > Changes since v1: https://lore.kernel.org/all/20230628121811.338655-1-tz.stoyanov@gmail.com/ > - Added one-time warning, suggested by Steven Rostedt. > Changed since v2: https://lore.kernel.org/lkml/20230630121627.833560-1-tz.stoyanov@gmail.com/ > - Added counter of successfully enabled eprobes, suggested by Steven Rostedt. > > kernel/trace/trace_eprobe.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c > index cb0077ba2b49..a0a704ba27db 100644 > --- a/kernel/trace/trace_eprobe.c > +++ b/kernel/trace/trace_eprobe.c > @@ -644,6 +644,7 @@ static int enable_trace_eprobe(struct trace_event_call *call, > struct trace_eprobe *ep; > bool enabled; > int ret = 0; > + int cnt = 0; > > tp = trace_probe_primary_from_call(call); > if (WARN_ON_ONCE(!tp)) > @@ -667,12 +668,25 @@ static int enable_trace_eprobe(struct trace_event_call *call, > if (ret) > break; > enabled = true; > + cnt++; > } > > if (ret) { > /* Failed to enable one of them. Roll back all */ > - if (enabled) > - disable_eprobe(ep, file->tr); > + if (enabled) { > + /* > + * It's a bug if one failed for something other than memory > + * not being available but another eprobe succeeded. > + */ > + WARN_ON_ONCE(ret != -ENOMEM); > + > + list_for_each_entry(pos, trace_probe_probe_list(tp), list) { > + ep = container_of(pos, struct trace_eprobe, tp); > + disable_eprobe(ep, file->tr); > + if (!--cnt) > + break; > + } > + } > if (file) > trace_probe_remove_file(tp, file); > else > -- > 2.41.0 > -- Masami Hiramatsu (Google)