I am debugging a Linux kernel in the VMPlayer on Ubuntu 12.04 configured a serial port to a file to see the debug information. However, each time when the kernel panics, only the backtrace stack were printed out instead of all the booting messages. This does not happend on VMPlayer Fusion. My .vmx file: serial1.present = "TRUE" serial1.fileType = "file" serial1.fileName = "~/tmp/serial.out" serial1.startConnected = "TRUE" msg.serial.file.open = "Replace" serial1.yieldOnMsrRead = "TRUE" My /etc/default/grub: GRUB_CMDLINE_LINUX_DEFAULT="quiet" GRUB_CMDLINE_LINUX="find_preseed=/preseed.cfg noprompt console=tty0 console=ttyS1,115200n8" How could I flush every message to both tty0 and ttyS1?