i.MX ProcessorsのトピックRe: freescale android kernel have scheduling problem !!!

freescale android kernel have scheduling problem !!!

yangaaron — Thu, 12 Dec 2013 10:33:27 GMT

I wrote a very simple Android application(AndroidGLSurfaceViewActivity.apk).mainly use opengl use muti-thread to draw frame on the screen

I tried to run on the freescale platform ( i.mx6q , 1GB Ram , android 4.0.4 , hdmi 1080p output )

It can't run more than one hour will cause the system to crash. (Kernel panic or rcu_preempt_state detected stalls on CPUs/tasks).

but it can run all night on the Android Emulator and Samsung Galaxy Note 8.0

PS : Android apk and program source code and detailed error messages, see attached file

Original Attachment has been moved to: rcu_preempt_state-detected-stalls-on-CPUstasks.txt.zip

Original Attachment has been moved to: AndroidGLSurfaceViewActivity.apk.zip

Original Attachment has been moved to: AndroidGLSurfaceViewActivity.7z.zip

Original Attachment has been moved to: Kernel-panic--not-syncing-Fatal-exception.txt.zip

Re: freescale android kernel have scheduling problem !!!

Chris1z — Fri, 13 Dec 2013 00:04:04 GMT

We have also seen similar crashes on our product that is based on SabreSD iMX6Q jb4.2.2-1.1.0-ga release with 2GB of memory. Kernel panics with a NULL pointer dereference or " rcu_preempt_state detected stalls". I ran your tests on our boards and saw the kernel panic a couple of times. I also saw sometimes the app would freeze and I would have stop and start it again.

I also tried your test on a few of our SabreSd (Rev C1 and Rev C2) boards. I didn't see the same specific kernel panic or rcu stall yet, but they did reboot a couple of times without any logs. The OOM killer seems to kick in pretty quickly too, maybe because SabreSd only has 1GB.

I am running a newer version of Android (and probably the kernel) than you. But regardless, your test does definitely reveals some issues on the iMX6.

Someone from Freescale please comment.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Fri, 13 Dec 2013 02:23:34 GMT

Yes . similar result with your when I upgrade our platform to android 4.2.2 .

it will reboot system and without any error logs in one hour.

i think seems to be a watchdog role because the kernel no response
.

Re: freescale android kernel have scheduling problem !!!

LeonardoSandova — Fri, 13 Dec 2013 20:00:40 GMT

aaronyang please mark it as 'unanswered'.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Mon, 16 Dec 2013 00:50:25 GMT

ok, i will open an new topic "freescale android kernel have scheduling problem ?"

Please reply as soon as possible solutions to the problem

thanks~

Re: freescale android kernel have scheduling problem !!!

Chris1z — Mon, 16 Dec 2013 01:02:08 GMT

aaronyang I think Leo just wanted you to mark this topic an "unanswered" so Freescale users will know to look at it. Thanks.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Mon, 16 Dec 2013 01:08:56 GMT

hello , chris1z

I know - but I do not see unmark option on this page .

Re: freescale android kernel have scheduling problem !!!

LeonardoSandova — Mon, 16 Dec 2013 14:32:56 GMT

Aaron, Chris

The issue has been escalated. Yesterday I tried on latest JB (4.3). and the issue is present. I am not an Android expert so I can not provide any useful insight for the moment.

Aaron,

on the other thread you created, just to avoid confusion, post a comment indicating that the updates will be done on this thread, which is the original.

Leo

Re: freescale android kernel have scheduling problem !!!

xiaoqianlin — Mon, 23 Dec 2013 02:20:36 GMT

This issue can be duplicated on MX6SDP JB4.2.2_1.1.0. I attached the log.

Re: freescale android kernel have scheduling problem !!!

xiaoqianlin — Tue, 07 Jan 2014 02:36:21 GMT

I tested this issue on JB4.3_1.1.0, this issue still can be duplicated

Re: freescale android kernel have scheduling problem !!!

XianzhongLi — Wed, 08 Jan 2014 06:55:28 GMT

"rcu_preempt_state detected stalls" could be fixed with the followng patch, please try

--- linux-3.0.35/arch/arm/plat-mxc/time.c.orig	2013-12-11 09:25:29.518910709 +1300
+++ linux-3.0.35/arch/arm/plat-mxc/time.c	2013-12-11 09:26:12.958912361 +1300

@@ -165,7 +165,8 @@

__raw_writel(tcmp, timer_base + V2_TCMP);

return 0;

+ return evt < 0x7fffffff &&

+ (int)(tcmp - __raw_readl(timer_base + V2_TCN)) < 0 ? ETIME : 0;

}

#ifdef DEBUG

Re: freescale android kernel have scheduling problem !!!

yangaaron — Wed, 08 Jan 2014 09:54:31 GMT

Hello , Xianzhong

I patch to our kernel and try run again on our freescale platform board ( i.mx6q , 1GB Ram , hdmi 1080p output )

Test results are as follows:
system hang up and no error message within an hour (android version 4.0.4)
system reboot and no error message within an hour (android version 4.2.2)
system reboot and no error message about two days (android version 4.3)

Re: freescale android kernel have scheduling problem !!!

lily_zhang — Mon, 13 Jan 2014 03:57:34 GMT

Hello, Aaron:

The above patch targets to resolve the issue "rcu_preempt_state detected stalls on CPUstasks". So from your test, do you still see "CPU stall" issue?

If it's resolved, the left issue is "system reboot and no error message sometimes". Can you please try to disable Watchdog? So we can check the sitatuions in this case.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Tue, 14 Jan 2014 01:24:59 GMT

Hi , Xiaoli

I think it is random ~

Its system crash situation occurs in the second performance without spending too much time (android jb 4.3)

About error message I only saw "rcu_preempt_state detected stalls on CPUstasks" message on android 4.0.4 before i patching it.

system hang up and no error message after patching it (android ics 4.0.4)

usually system would be direct reboot and no any error message when running on android jb 4.2 & 4.3 (whether patch it or not)

system hang up and no error message after i disabled watchdog(android jb 4.2 & 4.3)

Re: freescale android kernel have scheduling problem !!!

lily_zhang — Tue, 14 Jan 2014 02:42:18 GMT

To disable watchdog is to check the situation when the problem happens.

After reboot, it's difficult to get more useful information.

So to disable watchdog is not solution, just for debug purpose.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Tue, 14 Jan 2014 03:17:05 GMT

Hello , Xiaoli

Yes , I know

Thank you

Re: freescale android kernel have scheduling problem !!!

qiang_li-mpu_se — Thu, 16 Jan 2014 02:54:07 GMT

I tried this APK with "maxcpus=1", then only one CPU will be loaded in kernel, and I had also disabled the WDOG, running this APK, the system still will hang up without error messages.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Thu, 16 Jan 2014 03:03:54 GMT

Hello, Qiang

Yes, I know ~

Before I have done similar experiments

Thanks

Re: freescale android kernel have scheduling problem !!!

LeonardoSandova — Thu, 16 Jan 2014 19:22:32 GMT

Aaron, have you tried with maxcpus=0 ? this is not the same as =1, because =0 turns off SMP.

Re: freescale android kernel have scheduling problem !!!

yangaaron — Mon, 20 Jan 2014 00:47:43 GMT

No, I would set up one.

Thank you.