After patch kernel to PREEMPT_RT, TTY driver error activated. I comment spinlock around tty_flip_buffer_push() and all is OK. [NUC970_linux_kernel_bug.txt](https://github.com/OpenNuvoton/NUC970_Linux_Kernel/files/10664040/NUC970_linux_kernel_bug.txt) [03_nuc970_serial.patch](https://github.com/OpenNuvoton/NUC970_Linux_Kernel/files/10664056/03_nuc970_serial.patch)
After patch kernel to PREEMPT_RT, TTY driver error activated.
I comment spinlock around tty_flip_buffer_push() and all is OK.
NUC970_linux_kernel_bug.txt
03_nuc970_serial.patch