From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [for-next][PATCH 00/18] function_graph: Add separate depth counter to prevent trace corruption Date: Wed, 28 Nov 2018 16:00:21 -0500 Message-ID: <20181128160021.09acd1af@gandalf.local.home> References: <20181122002801.501220343@goodmis.org> <20181128203931.ym2rkya7a6agzzy3@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181128203931.ym2rkya7a6agzzy3@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Joe Lawrence Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , linux-arch@vger.kernel.org, Joel Fernandes , Masami Hiramatsu , Josh Poimboeuf , Andy Lutomirski , Frederic Weisbecker List-Id: linux-arch.vger.kernel.org On Wed, 28 Nov 2018 15:39:31 -0500 Joe Lawrence wrote: > Hi Steve, > > With your ftrace/urgent branch linked above, if I try a quick > function_graph test like the following: > > SYSFS=/sys/kernel/debug/tracing > > echo 0 > "$SYSFS/tracing_on" > echo cmdline_proc_show > "$SYSFS/set_graph_function" > echo function_graph > "$SYSFS/current_tracer" > echo 1 > "$SYSFS/tracing_on" > > I see a bunch of scheduler interrupt functions in the trace/trace_pipe > without even invoking cmdline_proc_show(). > > This tests works as expected with Linux 4.20-rc3 though: > > % cat /sys/kernel/debug/tracing/trace_pipe > 2) | cmdline_proc_show() { > 2) 0.320 us | seq_puts(); > 2) 0.030 us | seq_putc(); > 2) 1.352 us | } > > Operator error, or did the patchset break something? Nope, that does seem to be a bug :-/ -- Steve From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:35470 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726239AbeK2IDU (ORCPT ); Thu, 29 Nov 2018 03:03:20 -0500 Date: Wed, 28 Nov 2018 16:00:21 -0500 From: Steven Rostedt Subject: Re: [for-next][PATCH 00/18] function_graph: Add separate depth counter to prevent trace corruption Message-ID: <20181128160021.09acd1af@gandalf.local.home> In-Reply-To: <20181128203931.ym2rkya7a6agzzy3@redhat.com> References: <20181122002801.501220343@goodmis.org> <20181128203931.ym2rkya7a6agzzy3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Joe Lawrence Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , linux-arch@vger.kernel.org, Joel Fernandes , Masami Hiramatsu , Josh Poimboeuf , Andy Lutomirski , Frederic Weisbecker Message-ID: <20181128210021.kK-XBc09aA039mSZ7_itCZDg98hz6j7O7IAMQMi6GOE@z> On Wed, 28 Nov 2018 15:39:31 -0500 Joe Lawrence wrote: > Hi Steve, > > With your ftrace/urgent branch linked above, if I try a quick > function_graph test like the following: > > SYSFS=/sys/kernel/debug/tracing > > echo 0 > "$SYSFS/tracing_on" > echo cmdline_proc_show > "$SYSFS/set_graph_function" > echo function_graph > "$SYSFS/current_tracer" > echo 1 > "$SYSFS/tracing_on" > > I see a bunch of scheduler interrupt functions in the trace/trace_pipe > without even invoking cmdline_proc_show(). > > This tests works as expected with Linux 4.20-rc3 though: > > % cat /sys/kernel/debug/tracing/trace_pipe > 2) | cmdline_proc_show() { > 2) 0.320 us | seq_puts(); > 2) 0.030 us | seq_putc(); > 2) 1.352 us | } > > Operator error, or did the patchset break something? Nope, that does seem to be a bug :-/ -- Steve