Re: [PATCH 0/2] Avoid crashes by early (boot) consoles using init memory

From: Fabio M. Di Nitto
Date: Fri Jul 14 2017 - 08:58:04 EST

Hi Petr,

On 7/14/2017 2:51 PM, Petr Mladek wrote:
> Some early consoles have code and data in the init section. It makes some
> sense but this might cause problems when they are not replaced by
> the real console in time. The two patches fix the safequard and
> help to avoid the problems.
> I though about removing keep_bootcon option completely. But it is useful
> at least for now.

LetÂs just keep in mind that keep_bootcon was introduced only to debug
issues (read crashes or hangs) that could happen between disabling
bootconsole and enabling the real console. It shouldnÂt be used for
anything else really.

If the new code can replace keep_bootcon, by all mean, go for it :-)


> There is not an easy way to disable a particular bootconsole
> when the related real console is installed. Instead all bootconsoles are
> removed when the preferred (last on the commandline) console is registered.
> But this is a bit cumbersome and non-intuitive.
> In addition, the same problems might happen when the real console is
> registered using a deferred probe or when it is not registered at all
> for some reason.
> The patchset is based on and inspired by the original patch from
> Matt Redfearn, see the discussion starting by the mail
> Matt Redfearn (1):
> printk/console: Always disable boot consoles that use init memory
> before it is freed
> Petr Mladek (1):
> printk/console: Enhance the check for consoles using init memory
> kernel/printk/printk.c | 28 +++++++++++++++++-----------
> 1 file changed, 17 insertions(+), 11 deletions(-)