rcu_bh_state detected stall and rcu_preempt_state detected stalls in Android 6.0.1 (MarshMallow)

[winstonjacob]

Hi,

We are working in iMx6Q processor which runs on Android 6.0.1.(MarshMallow) and Linux Kernel version is 4.1.15. We are getting rcu_bh_state detected stall prints in dbug terminal while we run the processor for longer time. As per this comment,

https://community.nxp.com/thread/333368#comment-446520, patches will be applied for same issue in Linux Kernel version 3.10.17.

We are not able to apply the patches provided in the above thread directly since Linux Kernel Directory structure changed from 3.0.35 to 4.1.15. We went through the patches and observed that most of the patches were related to GPU functionality. We think that VIVANTE libraries were related to GPU functionality. We found out that one of the VIVANTE library in Marshmallow is lesser in file size than Kitkat.

VIVANTE Library	KitKat	Marshmallow	Nougat
libEGL_VIVANTE.so	50868	80556	90212
libGLESv1_CM_VIVANTE.so	246308	201616	252780
libGLESv2_VIVANTE.so	363344	651620	1009720

My questions are

1. Are we using latest VIVANTE library for Marsh Mallow? Did this drop in file size in Marsh Mallow is normal?
2. Is there any patches related to rcu_bh_state detected stall available for Marsh Mallow?

Regards,

Winston

[winstonjacob]

Hi Igor,

Is it possible to apply GPU ERRATA patch over our current Linux Kernel 4.1.15? if possible, can you share the patch link?

Thanks and Regards,

Winston

[igorpadykov]

Hi Winston

Linux Kernel 4.1.15 is old kernel and not more supported,

help with old kernels also may be obtained using:

Commercial Support and Engineering Services | NXP 

Best regards
igor

[winstonjacob]

Hi Igor,

We are planning to upgrade Kernel to 4.14.78. Is that kernel version is supported for Marshmallow? If complete kernel migration is not possible, we are planning to upgrade drivers alone? Is it correct to do like this? Since upgrading from Marshmallow will be tough on our side.

[igorpadykov]

Hi Winston

for supported kernels one can refer to NXP documentation

i.MX Software and Development Tools | NXP 

For helping with porting NXP has special service:

Commercial Support and Engineering Services | NXP 

Best regards
igor

[winstonjacob]

Hi Igor,

We checked our U-boot source, that ERRATA is already applied. Is there any other patches we can apply?

[igorpadykov]

Hi Winston

other reason may be gpu errata, which were fixed in new kernels.

So one can try not use gpu or migrate to newer android releases found on

i.MX Software and Development Tools | NXP 

Best regards
igor

[winstonjacob]

Hi Igor,

If we apply that GPU errata on top of Kernel will it fix the issue? If yes, Can you provide me the link to get that GPU errata patch?

[igorpadykov]

Hi Winston

also rcu_bh_state detected stall may be affected by arm errata, so one can check if

#define CONFIG_ARM_ERRATA are included in uboot:

mx6_common.h\configs\include - uboot-imx - i.MX U-Boot 

try Android 6.0.1 Marshmallow (M6.0.1_2.1.0, 4.1 kernel) Source Code  from

i.MX Software | NXP 

Best regards
igor
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