Re: [PATCH] pstore: Fix printing of duplicate boot messages to console

[Stephen Boyd]

Quoting Kees Cook (2020-01-27 15:27:33)
> On Thu, Jan 23, 2020 at 09:30:31PM +0530, Sai Prakash Ranjan wrote:
> > Since commit f92b070f2dc8 ("printk: Do not miss new messages
> > when replaying the log"), CON_PRINTBUFFER flag causes the
> > duplicate boot messages to be printed on the console when
> > PSTORE_CONSOLE and earlycon (boot console) is enabled.
> > Pstore console registers to boot console when earlycon is
> > enabled during pstore_register_console as a part of ramoops
> > initialization in postcore_initcall and the printk core
> > checks for CON_PRINTBUFFER flag and replays the log buffer
> > to registered console (in this case pstore console which
> > just registered to boot console) causing duplicate messages
> > to be printed. Remove the CON_PRINTBUFFER flag from pstore
> > console since pstore is not concerned with the printing of
> > buffer to console but with writing of the buffer to the
> > backend.
> 
> I agree this patch isn't the solution, but I'm trying to understand
> where better logic could be added. Is the issue that printk sees both
> earlycon and CON_PRINTBUFFER active? Can we add a new CON_* flag that
> means "not actually printing anything"? (Or maybe a new flag for
> non-printing to replace CON_PRINTBUFFER that lets pstore still work?)
> 

This seems to be fixed by commit def97da13651 ("printk: fix
exclusive_console replaying"). I think there's nothing to do.