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).
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  seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.
Add log level argument to unwind_backtrace() as a preparation for introducing show_stack_loglvl().
As a good side-effect arm_syscall() is now printing errors with the same log level as the backtrace.
e8d7b7353216 arm: add loglvl to unwind_backtrace()
arch/arm/include/asm/unwind.h | 3 ++-
arch/arm/kernel/traps.c | 6 +++---
arch/arm/kernel/unwind.c | 5 +++--
3 files changed, 8 insertions(+), 6 deletions(-)