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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 3BFE9C04EBD for ; Tue, 16 Oct 2018 18:05:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EBC9B21476 for ; Tue, 16 Oct 2018 18:05:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="PvJvc/Ef"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="l7ysdptI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBC9B21476 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727363AbeJQB4w (ORCPT ); Tue, 16 Oct 2018 21:56:52 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:58924 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727006AbeJQB4v (ORCPT ); Tue, 16 Oct 2018 21:56:51 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id DC38F612F6; Tue, 16 Oct 2018 18:05:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539713113; bh=v9UsiGiw9e1yioOSWt6WIEiPefDHfptpAdXO4v7qen0=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=PvJvc/EfVuRzsurhe4hoyc27qNJvBW2HDobOvi48/U6wCD86tQw9w7zW5yZSr4J8K J6Snsro9wSLeKRrgUBfMTMCa84Nxg6ZLRzKyTOYEijQQ8IaSyBH6pyUXa2Su6Y6ulg UsMJEqVj6CPdV57qj+tuOr3fpz2E/XBv+/yUrwf0= Received: from [192.168.43.47] (unknown [223.227.22.91]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 48673606DD; Tue, 16 Oct 2018 18:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539713112; bh=v9UsiGiw9e1yioOSWt6WIEiPefDHfptpAdXO4v7qen0=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=l7ysdptIb4aj0L4FfPU24NJEZoVU/BoO57L1KZtOyKvL0bPy3apP6yq2Ng2Z1xwmx MHuihzEoPX7eIeWjtkEQoCBuWrO19MuuTpo+E6POXiiJmbEbvIM08e/VqzbCLsRy5E 3KSugB9UhrfQeLVHDXi6HgfNimCjBdt1cNJCxvg4= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 48673606DD Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=saiprakash.ranjan@codeaurora.org Subject: Re: Crash in msm serial on dragonboard with ftrace bootargs To: Steven Rostedt Cc: Stephen Boyd , Bjorn Andersson , Andy Gross , David Brown , Jiri Slaby , "Ivan T. Ivanov" , Kees Cook , "Joel Fernandes (Google)" , Geliang Tang , Greg Kroah-Hartman , Pramod Gurav , linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Rajendra Nayak , Vivek Gautam , Sibi Sankar References: <1cae8f10-55f5-20ce-9105-30af6f88bd6e@codeaurora.org> <20181016112928.4b52afb5@gandalf.local.home> <8c2fb318-813d-81f1-1e2f-cdbc68353077@codeaurora.org> <20181016125721.236ada82@gandalf.local.home> <20181016134803.1b9260c1@gandalf.local.home> From: Sai Prakash Ranjan Message-ID: <472db11e-49a6-a1ee-e298-791ee1bbb10b@codeaurora.org> Date: Tue, 16 Oct 2018 23:35:00 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181016134803.1b9260c1@gandalf.local.home> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/16/2018 11:18 PM, Steven Rostedt wrote: > On Tue, 16 Oct 2018 23:06:24 +0530 > Sai Prakash Ranjan wrote: > >> On 10/16/2018 10:27 PM, Steven Rostedt wrote: >>> >>> OK, can you add to the command line: >>> >>> ftrace=function ftrace_filter=*schedule* >>> >>> to see if it's a specific function that may be causing the issue (but >>> hopefully it's not one of the scheduling functions that caused it). >>> >> >> Target boots fine with this. So its not scheduling functions that is >> causing it. Also I tried with ftrace_filter=*msm* just to be sure if >> tracing driver functions is causing any issue but its NOT. > > OK, seems that something is being traced that shouldn't be. > > When this happens after boot up, it's easy to bisect down to the > problem function. But since it's at boot up, it will take a lot longer. > > I would suggest to start by going down the alphabet. > > ftrace_filter=a* > ftrace_filter=b* > ftrace_filter=c* > [...] > > And at least find the letter the bad function starts with. > > Note, it could be more than one function (I've had that a couple of > times), and to find that out, you can test with "ftrace_notrace". Say > you find that the problem function starts with 'x'. You can do: > > ftrace_notrace=x* > > Which will trace all functions except those that start with an 'x', to > make sure it still boots. > > Remember, you still need to have ftrace=function for all of this. > > Once you find the letter of the function, you can try the next letter, > or perhaps come up with another method. I would say look at the > functions in /sys/kernel/debug/tracing/available_filter_functions, but > they don't list the init function (that can be traced). But you can > use /proc/kallsyms instead. > Ok got it, this sounds fun. I'll give it a try. Thanks -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation