Bugzilla: http://bugzilla.redhat.com/2023082



commit 85e3e7fbbb720b9897fba9a99659e31cbd1c082e
Author: John Ogness <john.ogness@linutronix.de>
Date:   Thu Jul 15 21:39:57 2021 +0206

    printk: remove NMI tracking

    All NMI contexts are handled the same as the safe context: store the
    message and defer printing. There is no need to have special NMI
    context tracking for this. Using in_nmi() is enough.

    There are several parts of the kernel that are manually calling into
    the printk NMI context tracking in order to cause general printk
    deferred printing:

        arch/arm/kernel/smp.c
        arch/powerpc/kexec/crash.c
        kernel/trace/trace.c

    For arm/kernel/smp.c and powerpc/kexec/crash.c, provide a new
    function pair printk_deferred_enter/exit that explicitly achieves the
    same objective.

    For ftrace, remove the printk context manipulation completely. It was
    added in commit 03fc7f9c ("printk/nmi: Prevent deadlock when
    accessing the main log buffer in NMI"). The purpose was to enforce
    storing messages directly into the ring buffer even in NMI context.
    It really should have only modified the behavior in NMI context.
    There is no need for a special behavior any longer. All messages are
    always stored directly now. The console deferring is handled
    transparently in vprintk().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
    [pmladek@suse.com: Remove special handling in ftrace.c completely.
Signed-off-by: Petr Mladek <pmladek@suse.com>
    Link: https://lore.kernel.org/r/20210715193359.25946-5-john.ogness@linutronix.de



Signed-off-by: Prarit Bhargava <prarit@redhat.com>