From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sai Prakash Ranjan Subject: Re: Crash in msm serial on dragonboard with ftrace bootargs Date: Fri, 19 Oct 2018 20:18:19 +0530 Message-ID: <9cafe321-87f6-98a3-3bda-c2f7a3d7fc67@codeaurora.org> References: <472db11e-49a6-a1ee-e298-791ee1bbb10b@codeaurora.org> <20181016141610.639b9000@gandalf.local.home> <20181016144123.24c47b38@gandalf.local.home> <7781815e-cba2-9e36-db6d-268298747876@codeaurora.org> <20181016150328.3450d718@gandalf.local.home> <20181017223334.29ca2837@vmware.local.home> <58d2474c-53cd-e6cb-2d25-db38d1a88da6@codeaurora.org> <20181018091706.62310b38@gandalf.local.home> <20181019041740.GB141835@joelaf.mtv.corp.google.com> <8a75f2d5-f1bd-504e-b545-ae2e2f61ca8f@codeaurora.org> <20181019095122.0f1c0946@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181019095122.0f1c0946@gandalf.local.home> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Steven Rostedt Cc: Joel Fernandes , Stephen Boyd , Bjorn Andersson , Andy Gross , David Brown , Jiri Slaby , Kees Cook , 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 List-Id: linux-arm-msm@vger.kernel.org On 10/19/2018 7:21 PM, Steven Rostedt wrote: > On Fri, 19 Oct 2018 12:24:05 +0530 > Sai Prakash Ranjan wrote: > >>>> Anyone see any problems here? >>> >>> This seems sane to me, he says in the other thread that he put 'notrace' to >>> the msm serial functions (which AIUI should prevent ftrace instrumentation) >>> and he still sees the issue. >>> >> >> Yes I did add notrace to all functions in msm serial and checked the >> objdump to make sure that those were not instrumented, and yet the >> target crashed. This doesnt seem like an issue with ftrace but rather >> with msm early con. > > The thing that still bothers me is that it boots fine without ftrace > running, and that it requires tracing something to cause the problem. > This tells me that ftrace has something to do with it. Perhaps it's > just changing the timing. > Yes tracing does cause issue but only if earlycon is present. If I disable earlycon, then even tracing wont cause any issue and target boots fine. > You said that if you add 'ftrace_filter=msm_read' to the command line, > it still crashes? > > So only tracing that function we have an issue, right? > Tracing msm_read does cause the crash, but that is not the only one causing the crash because even after "ftrace_notrace=msm_read" the board crashes which is why I suspect msm earlycon and not ftrace. Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation