On 11/6/19 9:52 AM, Michael Ellerman wrote:

Dmitry Safonov [off-list ref] writes:

quoted

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Yes, I've had bug reports where the stacktrace is missing, which is
annoying. Thanks for trying to fix the problem.

quoted

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <redacted>
Cc: linuxppc-dev@lists.ozlabs.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u (local)
Signed-off-by: Dmitry Safonov <redacted>
---
 arch/powerpc/kernel/process.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

This looks good to me.

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

Thanks for the review and time!

-- 
          Dmitry