On Tue 2018-09-11 11:30:39, Sergey Senozhatsky wrote: > On (09/10/18 16:57), Petr Mladek wrote: > > > > Good catch. > > > > > --- > > > > > > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > > > index c036f128cdc3..ede29a7ba6db 100644 > > > --- a/kernel/printk/printk.c > > > +++ b/kernel/printk/printk.c > > > @@ -2545,6 +2545,7 @@ void console_flush_on_panic(void) > > > * ensure may_schedule is cleared. > > > */ > > > console_trylock(); > > > + exclusive_console = NULL; > > > > This is not be enough. It would cause replying old messages > > on all consoles. > > Oh, that was intentional. I consider repeated messages to be less > problematic than the missing ones.
It makes some sense. But it might be problematic with slow consoles. I prefer to avoid it if there is a better solution. > > Most problems should probably be solved when we store console_seq > > before setting exclusive_console. Then we could clear > > exclusive_console when reaching the stored sequence number. > > > > Can this be that simple? ;-) > > This can work, yes. I'll try to cook up a patch later this week. > I also thought about doing it the way Linus, Jan Kara and Hannes > Reinecke proposed: > > - store the console_seq nr of the first oops_in_progress message > (oops_console_seq) and flush only messages that are in > [oops_console_seq - 200, log_next_seq] range, as opposed to complete > logbuf flush. > > Hannes asked for this several times. And it was in Jan's printk patches > long time ago (if I'm not mistaken - sorry if I am -- Jan said that Linus > wanted that "just N messages prior to oops" thing). > > Jan's patch: > > https://lore.kernel.org/lkml/1457964820-4642-3-git-send-email-sergey.senozhat...@gmail.com/T/#u The patch might be useful but it also might be controversial. It would deserve discussion with a wide audience in a dedicated thread. > > This reverts commit 375899cddcbb26881b03cb3fbdcfd600e4e67f4a. > > > > Reported-by: Hans de Goede <hdego...@redhat.com> > > Signed-off-by: Petr Mladek <pmla...@suse.com> > > Acked-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com> I have just pushed the patch into printk.git, for-4.19-rc4 branch. Note that I merged also a revert of the build fix commit ffaa619af1b06 ("printk: Fix warning about unused suppress_message_printing"). I am sorry that I missed it in the original patch. It is an obvious oneliner. It should not invalidate the acks. Best Regards, Petr
