From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935188AbcIPOdI (ORCPT ); Fri, 16 Sep 2016 10:33:08 -0400 Received: from mailout4.w1.samsung.com ([210.118.77.14]:57478 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935359AbcIPOcq (ORCPT ); Fri, 16 Sep 2016 10:32:46 -0400 X-AuditID: cbfec7f1-f79f46d0000008eb-ac-57dc028a877e Subject: Re: [ISSUE] Memleak in LED sysfs on heavy usage To: Greg KH Cc: Daniel Gorsulowski , "linux-leds@vger.kernel.org" , "linux-kernel@vger.kernel.org" From: Jacek Anaszewski Message-id: Date: Fri, 16 Sep 2016 16:32:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-version: 1.0 In-reply-to: <20160916140626.GB391@kroah.com> Content-type: text/plain; charset=windows-1252; format=flowed Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrOIsWRmVeSWpSXmKPExsWy7djP87pdTHfCDZonilpsaW5mtDi3YAaj xeVdc9gstr5Zx+jA4vHnwgtmj7cPAzw+b5ILYI7isklJzcksSy3St0vgyljf/IOt4KZcxaW+ 24wNjJMkuhg5OCQETCQ29OV2MXICmWISF+6tZ+ti5OIQEljKKHFu5SEo5zOjxJWuXYwQVSYS N/Y8gUosY5RY/2UNE4TzjFGif9pdJpAqYQELidXLzoJ1iAjISHQs2cMOUsQssIFR4vKxK2BF bAKGEj9fvAazeQXsJG7fOsQCchOLgKrE/GnaIKaoQITE7rupEBWCEj8m32MBsTkFdCUeNBxl B7GZBRwlHizayQphy0tsXvOWGWSVhEAzu8TKWS/ZIN6Uldh0gBniAReJ3bOWskLYwhKvjm9h h7BlJC5P7maB6J3MKHHx2E1WCGc1o8TGzk4WiCpriYb/v1ggtvFJTNo2nRliAa9ER5sQRImH xI1Vh6EWOEocebYIGlrnmSS+PpzJMoFRfhaSh2YheWIWkicWMDKvYhRJLS3OTU8tNtIrTswt Ls1L10vOz93ECEwOp/8d/7iD8f0Jq0OMAhyMSjy8K+beChdiTSwrrsw9xCjBwawkwhv+93a4 EG9KYmVValF+fFFpTmrxIUZpDhYlcd49C66ECwmkJ5akZqemFqQWwWSZODilGhhnOPTmNZh+ nhJT1/HwB0fyteIr4S6Hehg9V/IsWq557APnpan6Dq2PWLQY786am/5g+i8JzjmtM+yfCt98 8dZ59sL9Ma6/dt77nH/x3StWh5AT7jO0p1wNT/dsYZ1g4bFew0Jf9skr7/alsq2P1vmmZAcs mRx5oN/j4PnqdZrGu6/WTF15OcxXiaU4I9FQi7moOBEAjQN6TAoDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprBIsWRmVeSWpSXmKPExsVy+t/xK7pRTHfCDSbMYbTY0tzMaHFuwQxG i8u75rBZbH2zjtGBxePPhRfMHm8fBnh83iQXwBzlZpORmpiSWqSQmpecn5KZl26rFBripmuh pJCXmJtqqxSh6xsSpKRQlphTCuQZGaABB+cA92AlfbsEt4z1zT/YCm7KVVzqu83YwDhJoouR k0NCwETixp4nbBC2mMSFe+uBbC4OIYEljBJH1l9ggXCeMUp0rT3OAlIlLGAhsXrZWUYQW0RA RqJjyR52iKLzTBI3/y4B62AW2MAo8XXFDVaQKjYBQ4mfL14zgdi8AnYSt28dAiri4GARUJWY P00bJCwqECFxa9VHRogSQYkfk++BLeMU0JV40HCUHcRmFrCVWPB+HQuELS+xec1b5gmMArOQ tMxCUjYLSdkCRuZVjCKppcW56bnFRnrFibnFpXnpesn5uZsYgbGy7djPLTsYu94FH2IU4GBU 4uFdMfdWuBBrYllxZe4hRgkOZiUR3vC/t8OFeFMSK6tSi/Lji0pzUosPMZoC/TCRWUo0OR8Y x3kl8YYmhuaWhkbGFhbmRkZK4rxTP1wJFxJITyxJzU5NLUgtgulj4uCUamBcOivqS9TG7J8n yprkT99tzL+vUhC173XhbX2+U50eb1NFvPpKVu5YKlTZfKznobNXeGFP+KXlAcbyru+XNYoa fmzlmmr9ol9DmSWyIetZyN7l/Eki81bN47/3eF7MoUcVSy1ncpeq/Sx70Dgjn39Srd8etTlH E5uC27TfbfbZxeRSfo43W0KJpTgj0VCLuag4EQCpkzPYqwIAAA== X-MTR: 20000000000000000@CPGS X-CMS-MailID: 20160916143241eucas1p277f81b19fc3648f5646b77da4825fda8 X-Msg-Generator: CA X-Sender-IP: 182.198.249.180 X-Local-Sender: =?UTF-8?B?SmFjZWsgQW5hc3pld3NraRtTUlBPTC1TeXN0ZW0gRlcgIChN?= =?UTF-8?B?Qikb7IK87ISx7KCE7J6QG1NlbmlvciBTb2Z0d2FyZSBFbmdpbmVlcg==?= X-Global-Sender: =?UTF-8?B?SmFjZWsgQW5hc3pld3NraRtTUlBPTC1TeXN0ZW0gRlcgIChN?= =?UTF-8?B?QikbU2Ftc3VuZyBFbGVjdHJvbmljcxtTZW5pb3IgU29mdHdhcmUgRW5naW5l?= =?UTF-8?B?ZXI=?= X-Sender-Code: =?UTF-8?B?QzEwG0VIURtDMTBDRDAyQ0QwMjc1MjY=?= CMS-TYPE: 201P X-HopCount: 7 X-CMS-RootMailID: 20160916120853eucas1p2474a728f5fc725b094ad1addab507b58 X-RootMTR: 20160916120853eucas1p2474a728f5fc725b094ad1addab507b58 References: <37b949b3-6a9a-b8e3-c164-5ac2d44c9b3c@samsung.com> <4d51014d-c8fa-4687-cae8-1a8dd0f79beb@samsung.com> <7bb9a00e-0927-2fdc-5733-64bf922ebed6@samsung.com> <20160916140626.GB391@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/16/2016 04:06 PM, Greg KH wrote: > On Fri, Sep 16, 2016 at 03:41:09PM +0200, Jacek Anaszewski wrote: >> On 09/16/2016 02:08 PM, Daniel Gorsulowski wrote: >>> Hi Jacek, >>> >>> Am 16.09.2016 um 13:25 schrieb Jacek Anaszewski: >>>> On 09/16/2016 10:15 AM, Daniel Gorsulowski wrote: >>>>> Hi Jacek, >>>>> >>>>> Am 16.09.2016 um 09:31 schrieb Jacek Anaszewski: >>>>>> Hi Daniel, >>>>>> >>>>>> On 09/12/2016 10:50 AM, Daniel Gorsulowski wrote: >>>>>>> Hello! >>>>>>> >>>>>>> Please consider if I made something wrong, sending this issue. This is >>>>>>> my first contact to the LKML. >>>>>>> By mistake, I accessed an LED via /sys/class/leds subsystem very >>>>>>> fast in >>>>>>> an user application. I figured out, that the free user memory >>>>>>> decreased >>>>>>> constantly. So I tried to analyze the Problem and wrote a litte >>>>>>> script: >>>>>>> >>>>>>> #!/bin/sh >>>>>>> while [ 1 ]; do >>>>>>> echo 1 > /sys/class/leds/2a_service_yellow/brightness >>>>>>> echo 0 > /sys/class/leds/2a_service_yellow/brightness >>>>>>> done >>>>>>> >>>>>>> And voila, I was able to reproduce the problem. >>>>>>> So I add a bit more debugging: >>>>>>> >>>>>>> #!/bin/sh >>>>>>> cnt=0 >>>>>>> while [ 1 ]; do >>>>>>> if [ `expr $cnt % 1000` -eq 0 ]; then >>>>>>> free | grep Mem: | cut -d' ' -f25 >>>>>>> fi >>>>>>> echo 1 > /sys/class/leds/2a_service_yellow/brightness >>>>>>> echo 0 > /sys/class/leds/2a_service_yellow/brightness >>>>>>> let "cnt++" >>>>>>> done >>>>>>> >>>>>>> And huh? No memory is eaten anymore. So it looks like, the problem >>>>>>> only >>>>>>> occours on heavy (fast) usage of /sys/class/leds subsystem. >>>>>>> >>>>>>> I rewrote the script and toggled a GPIO pin, but there was no problem >>>>>>> recognizable. >>>>>> >>>>>> I've been unable to reproduce the problem with leds-aat1290 driver >>>>>> and Samsung M0 board. It must be driver specific issue. >>>>>> What driver did you use? >>>>>> >>>>> I defined LEDS_GPIO and so I'm using leds-gpio driver. >>>>> danielg@debby:~/opt/prj/ti-linux-kernel$ cat .config | grep LEDS | grep >>>>> -v "^# " >>>>> CONFIG_INPUT_LEDS=y >>>>> CONFIG_NEW_LEDS=y >>>>> CONFIG_LEDS_CLASS=y >>>>> CONFIG_LEDS_GPIO=y >>>>> CONFIG_LEDS_TRIGGERS=y >>>>> CONFIG_LEDS_TRIGGER_TIMER=y >>>>> CONFIG_LEDS_TRIGGER_ONESHOT=y >>>>> CONFIG_LEDS_TRIGGER_HEARTBEAT=y >>>>> CONFIG_LEDS_TRIGGER_GPIO=y >>>>> CONFIG_LEDS_TRIGGER_DEFAULT_ON=y >>>>> CONFIG_LEDS_TRIGGER_TRANSIENT=y >>>>> >>>> >>>> Unfortunately I am still unable to reproduce the problem with leds-gpio. >>>> I'm not observing any heavy usage with your test case: >>>> >>>> ~#free >>>> total used free shared buffers >>>> cached >>>> Mem: 1028092 61364 966728 0 8416 22396 >>>> -/+ buffers/cache: 30552 997540 >>>> Swap: 0 0 0 >>>> >>>> >>>> Actually you didn't give any numbers. What kernel version are you using? >>>> >>> As I wrote, the problems occurred in vanilla 4.6 kernel, but also in 4.4 >>> kernel (with PREEMPT-RT Patchset). >> >> Heh, funny coincidence. I was testing this on recent linux-leds.git, >> for-next branch and was not able to detect the issue. It started to >> appear after resetting HEAD to 4.8-rc2 base. Finally it turned out >> that what fixes the issue is the most recent commit [1]. >> >> Further investigation revealed that this is kobject_uevent_env(), >> called from led_trigger_set(), which causes memory leaks when called >> with high frequency. > > Really? Where in kobject_uevent_env() is the memory leak? I'll chase it down when and will let you know. This may be non-trivial issue as it suffices to add "sleep 0.1" between brightness setting operations to prevent it. -- Best regards, Jacek Anaszewski