From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48848 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750929AbdJBJlI (ORCPT ); Mon, 2 Oct 2017 05:41:08 -0400 Subject: Patch "tracing: Fix trace_pipe behavior for instance traces" has been added to the 3.18-stable tree To: tahsin@google.com, gregkh@linuxfoundation.org, rostedt@goodmis.org Cc: , From: Date: Mon, 02 Oct 2017 11:41:14 +0200 Message-ID: <1506937274215146@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled tracing: Fix trace_pipe behavior for instance traces to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tracing-fix-trace_pipe-behavior-for-instance-traces.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 75df6e688ccd517e339a7c422ef7ad73045b18a2 Mon Sep 17 00:00:00 2001 From: Tahsin Erdogan Date: Sun, 17 Sep 2017 03:23:48 -0700 Subject: tracing: Fix trace_pipe behavior for instance traces From: Tahsin Erdogan commit 75df6e688ccd517e339a7c422ef7ad73045b18a2 upstream. When reading data from trace_pipe, tracing_wait_pipe() performs a check to see if tracing has been turned off after some data was read. Currently, this check always looks at global trace state, but it should be checking the trace instance where trace_pipe is located at. Because of this bug, cat instances/i1/trace_pipe in the following script will immediately exit instead of waiting for data: cd /sys/kernel/debug/tracing echo 0 > tracing_on mkdir -p instances/i1 echo 1 > instances/i1/tracing_on echo 1 > instances/i1/events/sched/sched_process_exec/enable cat instances/i1/trace_pipe Link: http://lkml.kernel.org/r/20170917102348.1615-1-tahsin@google.com Fixes: 10246fa35d4f ("tracing: give easy way to clear trace buffer") Signed-off-by: Tahsin Erdogan Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4430,7 +4430,7 @@ static int tracing_wait_pipe(struct file * * iter->pos will be 0 if we haven't read anything. */ - if (!tracing_is_on() && iter->pos) + if (!tracer_tracing_is_on(iter->tr) && iter->pos) break; mutex_unlock(&iter->mutex); Patches currently in stable-queue which might be from tahsin@google.com are queue-3.18/tracing-fix-trace_pipe-behavior-for-instance-traces.patch