Deadlock under load with Linux 5.9 and other recent kernels

[Jens Axboe]

On 9/26/20 1:55 AM, Christian Hewitt wrote:
> I am using an ARM SBC device with Amlogic S922X chip (Beelink
> GS-King-X, an Android STB) to boot the Kodi mediacentre distro
> LibreELEC (which I work on) although the issue is also reproducible
> with Manjaro and Armbian on the same hardware, and with the GT-King
> and GT-King Pro devices from the same vendor - all three devices are
> using a common dtsi:
> 
> https://github.com/chewitt/linux/blob/amlogic-5.9-integ/arch/arm64/boot/dts/amlogic/meson-g12b-gsking-x.dts
> https://github.com/chewitt/linux/blob/amlogic-5.9-integ/arch/arm64/boot/dts/amlogic/meson-g12b-gtking-pro.dts
> https://github.com/chewitt/linux/blob/amlogic-5.9-integ/arch/arm64/boot/dts/amlogic/meson-g12b-gtking.dts
> https://github.com/chewitt/linux/blob/amlogic-5.9-integ/arch/arm64/boot/dts/amlogic/meson-g12b-w400.dtsi
> 
> I have schematics for the devices, but can only share those privately
> on request.
> 
> For testing I am booting LibreELEC from SD card. The box has a 4TB
> SATA drive internally connected with a USB > SATA bridge, see dmesg:
> http://ix.io/2yLh and I connect a USB stick with a 4GB ISO file that I
> copy to the internal SATA drive. Within 10-20 seconds of starting the
> copy the box deadlocks needing a hard power cycle to recover. The
> timing of the deadlock is variable but the device _always_ deadlocks.
> Although I am using a simple copy use-case, there are similar reports
> in Armbian forums performing tasks like installs/updates that involve
> I/O loads.
> 
> Following advice in the #linux-amlogic IRC channel I added
> CONFIG_SOFTLOCKUP_DETECTOR and CONFIG_DETECT_HUNG_TASK and was able to
> get output on the HDMI screen (it is not possible to connect to UART
> pins without destroying the box case). If you advance the following
> video frame by frame in VLC you can see the output:
> 
> https://www.dropbox.com/s/klvcizim8cs5lze/lockup_clip.mov?dl=0

Try with this patch:

https://lore.kernel.org/linux-block/20200925191902.543953-1-shakeelb@google.com/

-- 
Jens Axboe