s390: add show_stack_loglvl()
authorDmitry Safonov <dima@arista.com>
Tue, 9 Jun 2020 04:31:20 +0000 (21:31 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 9 Jun 2020 16:39:11 +0000 (09:39 -0700)
commit8539c1288ddc23eef0fe71e1bcecc04b3fc6a9ee
tree93d0a104649cc8ea04d3d6840040dd6aea021ac4
parent0b3d43657489711bf927998fde82b5cc575d9400
s390: add show_stack_loglvl()

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 [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().

[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200418201944.482088-29-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/s390/kernel/dumpstack.c