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Dmitry Safonov d46b3df78a x86: add missing const qualifiers for log_lvl
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.

Keep log_lvl const show_trace_log_lvl() and printk_stack_address() as the
new generic show_stack_loglvl() wants to have a proper const qualifier.

And gcc rightfully produces warnings in case it's not keept:
arch/x86/kernel/dumpstack.c: In function `show_stack':
arch/x86/kernel/dumpstack.c:294:37: warning: passing argument 4 of `show_trace_log_lv ' discards `const' qualifier from pointer target type [-Wdiscarded-qualifiers]
  294 |  show_trace_log_lvl(task, NULL, sp, loglvl);
      |                                     ^~~~~~
arch/x86/kernel/dumpstack.c:163:32: note: expected `char *' but argument is of type `const char *'
  163 |    unsigned long *stack, char *log_lvl)
      |                          ~~~~~~^~~~~~~

[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: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200418201944.482088-41-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:12 -07:00
arch x86: add missing const qualifiers for log_lvl 2020-06-09 09:39:12 -07:00
block for-5.8/drivers-2020-06-01 2020-06-02 15:37:03 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: engine - do not requeue in case of fatal error 2020-05-28 17:27:52 +10:00
Documentation remoteproc updates for v5.8 2020-06-08 13:01:08 -07:00
drivers remoteproc updates for v5.8 2020-06-08 13:01:08 -07:00
fs The highlights are: 2020-06-08 12:49:18 -07:00
include kallsyms/printk: add loglvl to print_ip_sym() 2020-06-09 09:39:10 -07:00
init kernel/sysctl: support setting sysctl parameters from kernel command line 2020-06-08 11:05:56 -07:00
ipc ipc/namespace.c: use a work queue to free_ipc 2020-06-08 11:05:56 -07:00
kernel kallsyms/printk: add loglvl to print_ip_sym() 2020-06-09 09:39:10 -07:00
lib Merge branch 'akpm' (patches from Andrew) 2020-06-08 11:11:38 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'akpm' (patches from Andrew) 2020-06-08 11:11:38 -07:00
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sound powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
tools kallsyms/printk: add loglvl to print_ip_sym() 2020-06-09 09:39:10 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
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Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
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README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.