The latest printk patches have been submitted and merged for the Linux 6.11 kernel. The printk updates take another step toward the long-in-development work around threaded console printing / non-blocking "NBCON" consoles as the last major step to allow the real-time "RT" kernel patches to land .

The printk changes needed to unblock the real-time kernel support from landing isn't over the finish line yet but with Linux 6.11 is another step in the right direction.

SUSE's Petr Mladek explained in the printk pull request for Linux 6.11:

"Next preparation step for introducing printk kthreads. This part wires up flushing consoles via con->write_atomic() callback.

The write_atomic() callback can be used for flushing nbcon consoles in any context. It is needed when the console could not be reliably
flushed using the printk kthread...."

These printk additions have been merged and now in Linux Git for the v6.11 cycle.