linux-kernel - Re: [RFC][PATCH 00/12] various perf fixes

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Message-ID: <CACT4Y+ZwzJTqfbG8wo8fx5sUFheUmPBADr4Y24s7k-LiO39xmw@mail.gmail.com>
Date:	Mon, 15 Feb 2016 17:38:36 +0100
From:	Dmitry Vyukov <dvyukov@...gle.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Stephane Eranian <eranian@...gle.com>,
	LKML <linux-kernel@...r.kernel.org>, vince@...ter.net,
	Andi Kleen <andi@...stfloor.org>, jolsa@...hat.com,
	Thomas Gleixner <tglx@...utronix.de>,
	Arnaldo Carvalho de Melo <acme@...radead.org>
Subject: Re: [RFC][PATCH 00/12] various perf fixes

On Mon, Feb 15, 2016 at 5:35 PM, Dmitry Vyukov <dvyukov@...gle.com> wrote:
> On Mon, Feb 15, 2016 at 5:29 PM, Peter Zijlstra <peterz@...radead.org> wrote:
>> On Thu, Jan 14, 2016 at 11:05:50AM +0100, Dmitry Vyukov wrote:
>>> There is a way to run it without coverage on a local machine.
>>>
>>> First, you need to setup Go toolchain: download latest Go distribution
>>> from https://golang.org/dl:
>>> https://storage.googleapis.com/golang/go1.5.3.linux-amd64.tar.gz
>>> Unpack it to $HOME/go1.5.
>>>
>>> $ export GOROOT=$HOME/go1.5
>>
>>> $ export GOPATH=$HOME/gopath
>>
>> So after I put that in a profile.d file:
>>
>>> Download syzkaller sources:
>>>
>>> $ go get github.com/google/syzkaller
>>
>> package github.com/google/syzkaller: no buildable Go source files in /root/gopath/src/github.com/google/syzkaller
>>
>>> Build necessary syzkaller binaries:
>>>
>>> $ cd $GOPATH/src/github.com/google/syzkaller
>>> $ make
>>
>> That seems to have done its thing
>>
>>> Then save the following content into
>>> $GOPATH/src/github.com/google/syzkaller/perf.cfg
>>>
>>
>> {
>>         "http": "localhost:50000",
>>         "workdir": "root/gopath/src/github.com/google/syzkaller/workdir",
>>         "syzkaller": "/root/gopath/src/github.com/google/syzkaller",
>>         "vmlinux": "-",
>>         "type": "local",
>>         "count": 1,
>>         "procs": 160,
>>         "nocover": true,
>>         "nodropprivs": true,
>>         "enable_syscalls": [
>>                 "perf_event_open",
>>                 "ioctl$PERF*",
>>                 "prctl$void",
>>                 "bpf$*",
>>                 "sched_yield"
>>         ]
>> }
>>
>>> Alter paths as necessary. Also you can change procs parameter (number
>>> of parallel test processes), something like NCPU*4 would be a good
>>> number. Also you can add additional syscalls to the mix.
>>
>> per the above
>>
>>> Then run:
>>>
>>> $ bin/syz-manager -config perf.cfg
>>>
>>> If you run it on a separate test machine, then scp syzkaller/bin dir
>>> and perf.cfg to the machine (the syzkaller param in config is where it
>>> will search for the bin dir).
>>>
>>> If syz-manager does not appear to be doing anything useful, then pleas
>>> run it in the following mode and post output:
>>>
>>> $ bin/syz-manager -config perf.cfg -v 1 -debug
>>
>> root@...-ep:~/gopath/src/github.com/google/syzkaller# bin/syz-manager -config perf.cfg -v 1 -debug
>> 2016/02/15 17:12:50 bad config syzkaller param: can't find bin/syz-execprog
>>
>> And its right, no such thing as bin/syz-execprog
>
>
> Please also do:
>
> $ make execprog
>
> And replace:
>
>         "nocover": true,
>         "nodropprivs": true,
>
> in config file with:
>
>         "cover": false,
>         "dropprivs": false,
>
> (that's changed since I wrote the instructions).


Just to compensate the pain, here is what I've just got when
re-enabled perf in my config :)

2016/02/15 16:52:18 qemu-15: saving crash 'WARNING: CPU: 0 PID: 18465
at kernel/events/core.c:2743 ctx_sched_in+0x255/0x17f0()' to
crash-qemu-15-1455551538366997265
2016/02/15 16:54:02 qemu-17: saving crash 'WARNING: CPU: 0 PID: 1072
at kernel/events/core.c:2743 ctx_sched_in+0x255/0x17f0()' to
crash-qemu-17-1455551642205132730
2016/02/15 16:54:44 qemu-30: saving crash 'WARNING: CPU: 3 PID: 19858
at kernel/events/core.c:2122 __perf_install_in_context+0x1c4/0x220()'
to crash-qemu-30-1455551684741709699
2016/02/15 16:55:02 qemu-20: saving crash 'WARNING: CPU: 2 PID: 9873
at kernel/events/core.c:226 event_function+0x359/0x3e0()' to
crash-qemu-20-1455551702744185903
2016/02/15 16:56:22 qemu-27: saving crash 'WARNING: CPU: 3 PID: 10602
at kernel/events/core.c:2122 __perf_install_in_context+0x1c4/0x220()'
to crash-qemu-27-1455551782768040747
2016/02/15 16:56:45 qemu-27: saving crash 'WARNING: CPU: 0 PID: 12779
at kernel/events/core.c:8693 perf_event_exit_task+0x708/0x900()' to
crash-qemu-27-1455551805030612662
2016/02/15 16:56:49 qemu-2: saving crash 'WARNING: CPU: 3 PID: 17062
at kernel/events/core.c:226 event_function+0x359/0x3e0()' to
crash-qemu-2-1455551809378028704
2016/02/15 16:56:58 qemu-20: saving crash 'WARNING: CPU: 3 PID: 22426
at kernel/events/core.c:2743 ctx_sched_in+0x255/0x17f0()' to
crash-qemu-20-1455551818913067860
2016/02/15 16:57:08 qemu-33: saving crash 'WARNING: CPU: 3 PID: 23837
at kernel/events/core.c:2122 __perf_install_in_context+0x1c4/0x220()'
to crash-qemu-33-1455551828622810673
2016/02/15 16:57:11 qemu-27: saving crash 'INFO: rcu_sched detected
stalls on CPUs/tasks:' to crash-qemu-27-1455551831109315050
2016/02/15 16:57:34 qemu-33: saving crash 'INFO: rcu_sched
self-detected stall on CPU' to crash-qemu-33-1455551854588053356
2016/02/15 16:57:44 qemu-33: saving crash 'BUG: workqueue lockup -
pool cpus=0 node=0 flags=0x0 nice=-20 stuck for 34s!' to
crash-qemu-33-1455551864688663395