Hello, On Wed, Jul 28, 2021 at 4:07 PM Petr Mladek <pmladek@xxxxxxxx> wrote: > [...] > > I guess that you have seen the following message printed by > console_on_rootfs(): > > "Warning: unable to open an initial console." > > This function is responsible for opening stdin, stdout, stderr > file to be used by the init process. > > I am not sure how this is supposed to work with the pivot_root > and initramfs. > > > Some more details: > > console_on_rootfs() tries to open /dev/console. It is created > by tty_init(). The open() callback calls: > > + tty_kopen() > + tty_lookup_driver() > + console_device() > > , where console_device() iterates over all registered consoles > and returns the first with tty binding. > > There is ttynull_console that might be used as a fallback. But I > am not sure if this is what you want. I didn't figure out the relation between initramfs and initial console, could you please tell me how this warning came up? I can't reproduce it in qemu with this command: qemu-system-x86_64 -nographic -m 2048M -smp cores=4,sockets=1 -s -kernel ./bzImage -initrd ./rootfs.cpio -append "rdinit=/init console=ttyS0" Thanks! Menglong Dong > > Best Regards, > Petr
