Hi everyone, I'm using Linux 5.15.24-rt31 kernel with PREEMPT_RT enabled, on my RK3308 board. I set up f_rndis gadget with the following script, and plugged my board to a x86 Linux computer running 5.15.25 kernel: #!/bin/sh cd /sys/kernel/config/usb_gadget mkdir g_smartcross; cd g_smartcross echo 0xF055 > idVendor echo 0xCAFE > idProduct mkdir strings/0x409 echo "SmartCross" > strings/0x409/manufacturer echo "SC-1 USB Device" > strings/0x409/product mkdir configs/c.1 mkdir functions/rndis.usb0 echo EF > functions/rndis.usb0/class echo 4 > functions/rndis.usb0/subclass echo 1 > functions/rndis.usb0/protocol ln -s functions/rndis.usb0 configs/c.1 echo ff400000.usb > UDC I started a HTTP server using python3 -m http.server on the x86 computer, and executed curl on my board to download a 100MB file from the computer. I got the following kernel logs from serial console of the board: % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 7 100M 7 7500k 0 0 7217k 0 0:00:14 0:00:01 0:00:13 7218k[ 23.002846] sched: RT throttling activated 23 100M 23 23.4M 0 0 5948k 0 0:00:17 0:00:04 0:00:13 5948k[ 25.992869] NOHZ tick-stop error: Non-RCU local softi! [ 25.993834] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #80!!! [ 25.994833] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #80!!! [ 25.995832] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #80!!! [ 25.995885] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #180!!! [ 25.996831] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #180!!! [ 25.997830] NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #180!!! If I turn off PREEMPT_RT, there won't be any errors while downloading. I believe this problem is not tied to any specific board, and anyone can reproduce this problem using a Raspberry Pi (Although I didn't try because I don't have one). I would like to ask for assistance regarding this problem.
