On Wed 2022-06-15 10:10:42, Paul E. McKenney wrote: > On Wed, Jun 15, 2022 at 06:28:03PM +0200, Petr Mladek wrote: > > There are reports that console kthreads prevented printing > > messages during panic() or shutdown(), see > > BugLink: https://lore.kernel.org/r/20220610205038.GA3050413@paulmck-ThinkPad-P17-Gen-1 > > BugLink: https://lore.kernel.org/r/CAMdYzYpF4FNTBPZsEFeWRuEwSies36QM_As8osPWZSr2q-viEA@xxxxxxxxxxxxxx > > > > In both situations, printk() correctly tries to flush the consoles > > directly but it fails to get the global console_lock(). Both > > problems went away with these patches: > > > > 1st patch blocks console kthreads so that they do not start > > handling new messages when the direct printing is preferred > > by the system state. It is probably enough on its own. It > > solves the problem when the kthreads actively did > > the wrong thing. > > > > 2nd patch allows to wait for the console kthreads to release > > the lock in any context. It should make it more reliable. > > It would have been useful even for the legacy code. > > Thank you! > > For the series: > > Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Thanks a lot for testing. I have pushed it into printk/linux.git, branch rework/kthreads to give it a spin in linux-next. Best Regards, Petr
