Re: [PATCH 26/50] powerpc: Add show_stack_loglvl()

[Dmitry Safonov]

On 11/6/19 9:52 AM, Michael Ellerman wrote:
> Dmitry Safonov <dima@xxxxxxxxxx> writes:
>> 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.
> 
>> 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@xxxxxxxxxxxxxxxxxxx>
>> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>> Cc: Paul Mackerras <paulus@xxxxxxxxx>
>> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
>> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@xxxxxxxxxx/T/#u
>> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
>> ---
>>  arch/powerpc/kernel/process.c | 18 +++++++++++++-----
>>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> This looks good to me.
> 
> Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> (powerpc)

Thanks for the review and time!

-- 
          Dmitry