From mboxrd@z Thu Jan 1 00:00:00 1970 From: beanhuo@micron.com (Bean Huo (beanhuo)) Date: Thu, 22 Sep 2016 08:36:41 +0000 Subject: ftrace function_graph causes system crash In-Reply-To: <20160921141705.6ab0be03@gandalf.local.home> References: <7d0e88fff8e64591ac31be3adbbf763c@SIWEX5A.sing.micron.com> <20160920100716.131d3647@gandalf.local.home> <0e38f79fdc1f4671943da74764c15050@SIWEX5A.sing.micron.com> <20160921171307.3fb84c87@xhacker> <20160921141705.6ab0be03@gandalf.local.home> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > -----Original Message----- > From: Steven Rostedt [mailto:rostedt at goodmis.org] > Sent: Mittwoch, 21. September 2016 20:17 > To: Jisheng Zhang > Cc: Bean Huo (beanhuo) ; Zoltan Szubbocsev > (zszubbocsev) ; catalin.marinas at arm.com; > will.deacon at arm.com; rfi at lists.rocketboards.org; linux- > kernel at vger.kernel.org; mingo at redhat.com; linux-arm- > kernel at lists.infradead.org > Subject: Re: ftrace function_graph causes system crash > > On Wed, 21 Sep 2016 17:13:07 +0800 > Jisheng Zhang wrote: > > > I'm not sure whether the commit d6df3576e6b4 > ("clocksource/drivers/arm_global_timer > > : Prevent ftrace recursion") can fix this issue. > > > > this commit is merged since v4.3, I noticed your kernel version is v4.0 > > BTW, yes, that would be the fix. > > -- Steve > > > > > Thanks, > > Jisheng > > > > > Do you know now how to deeply debug and trace which line is wrong > through Ftrace? > > > Hi, Steven and Jisheng Thanks to both warm-hearted guys. I merged d6df3576e6b4 patch into my kernel 4.0. Then it is true, no cash appears again. I have one more question that current ftrace can trace DMA latency, include mapping and unmapping? Means I want to know when one BIO request be completed. Just like blktrace. But blktrace can not tell me the function calling sequence. --Bean