On Wed 2018-06-20 10:55:25, Sergey Senozhatsky wrote: > On (06/19/18 12:52), Petr Mladek wrote: > > > But when I set /sys/module/printk/parameters/ignore_loglevel I naturally > > > expect it to take an immediate action. Without waiting for the consoles > > > to catch up and to discard N messages [if the consoles were behind the > > > logbuf head]. > > > > Yeah, I understand this view. I thought about it as well. But did you > > ever needed this behavior in the real life? > > > > I personally changed ignore_loglevel only before I wanted to reproduce a > > bug. Then it would be perfectly fine to handle it only in > > vprintk_emit(). In fact, it would be even better because it would > > affect only messages that happened after I triggered the bug. > > So maybe the patch can stand the way it is, after all. JFI, still haven't > seen those "helps in real life a lot" examples, tho.
I have personally seen these races when testing printk in NMI. I combined iptables logging, ping -f and sysrq-l. I am not sure how often they happen in the real life but I could understand that it might be annoying. This patch goes in the right direction and nobody really blocks it. Therefore I pushed it into printk.git, branch for-4.19. Best Regards, Petr
