On (03/11/19 13:04), John Ogness wrote: > > Great catch! > > Yes, thanks! > > > I think that it is doable to guard the list using RCU. > > I think it would be enough to take the prb_cpulock when modifying the > console linked list. That will keep printk_emergency() out until the > list has been updated. (registering/unregistering consoles is not > something that happens often.) console_sem can be a bit more than just registering/unregistering. Especially when it comes to VT, fbcon and ioctls. $ git grep console_lock drivers/tty/ | wc -l 82 $ git grep console_lock drivers/video/fbdev/ | wc -l 80 -ss
