Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757369Ab3GYS7H (ORCPT ); Thu, 25 Jul 2013 14:59:07 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:2231 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756252Ab3GYS7E (ORCPT ); Thu, 25 Jul 2013 14:59:04 -0400 X-Authority-Analysis: v=2.0 cv=aqMw+FlV c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=_6S4gJz81GoA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=UirpL7NoV14A:10 a=bLUb8Y6-K0ZtXP1s44IA:9 a=QEXdDO2ut3YA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-ID: <1374778741.3356.181.camel@gandalf.local.home> Subject: Re: __ftrace_hash_rec_update FTRACE_WARN_ON. From: Steven Rostedt To: Steve Hodgson Cc: =?ISO-8859-1?Q?J=F6rn?= Engel , Dave Jones , linux-kernel@vger.kernel.org Date: Thu, 25 Jul 2013 14:59:01 -0400 In-Reply-To: References: <20130705142629.GA325@redhat.com> <1373036034.22688.155.camel@gandalf.local.home> <20130724160422.GA3641@logfs.org> <1374715444.3356.163.camel@gandalf.local.home> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1281 Lines: 45 On Wed, 2013-07-24 at 22:46 -0700, Steve Hodgson wrote: > No, nothing so complicated. > > I added symbols from a kernel module into > /sys/kernel/debug/tracing/set_ftrace_filter, enabled tracing, then > unloaded the kernel module. > > Which I'll admit is a stupid thing to do. I was then punished for my > stupidity by being unable to use ftrace until the next reboot. It's not stupid. ftrace should be robust enough to handle this. Anyway, thank you, I found a reproducer. Removing the module isn't good enough. You need to load it again. # cd /sys/kernel/debug/tracing # cat set_ftrace_filter #### all functions enabled #### # modprobe uinput # echo uniput_release > set_ftrace_filter # cat set_ftrace_filter uinput_release [uinput] # rmmod uinput # cat set_ftrace_filter # # note this is empty # modprobe uinput # cat set_ftrace_filter uinput_release [uinput] # # '' # echo > set_ftrace_filter [BOOM] Now that I know what's the problem, it shouldn't be too hard to fix. Thanks! -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/