Pull Kbuild updates from Masahiro Yamada:

 - Use /usr/bin/env for shebang lines in scripts

 - Remove useless -Wnested-externs warning flag

 - Update documents

 - Refactor log handling in modpost

 - Stop building modules without MODULE_LICENSE() tag

 - Make the insane combination of 'static' and EXPORT_SYMBOL an error

 - Improve genksyms to handle _Static_assert()

* tag 'kbuild-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  Documentation/kbuild: Document platform dependency practises
  Documentation/kbuild: Document COMPILE_TEST dependencies
  genksyms: Ignore module scoped _Static_assert()
  modpost: turn static exports into error
  modpost: turn section mismatches to error from fatal()
  modpost: change license incompatibility to error() from fatal()
  modpost: turn missing MODULE_LICENSE() into error
  modpost: refactor error handling and clarify error/fatal difference
  modpost: rename merror() to error()
  kbuild: don't hardcode depmod path
  kbuild: doc: document subdir-y syntax
  kbuild: doc: clarify the difference between extra-y and always-y
  kbuild: doc: split if_changed explanation to a separate section
  kbuild: doc: merge 'Special Rules' and 'Custom kbuild commands' sections
  kbuild: doc: fix 'List directories to visit when descending' section
  kbuild: doc: replace arch/$(ARCH)/ with arch/$(SRCARCH)/
  kbuild: doc: update the description about kbuild Makefiles
  Makefile.extrawarn: remove -Wnested-externs warning
  tweewide: Fix most Shebang lines

Change every shebang which does not need an argument to use /usr/bin/env.
This is needed as not every distro has everything under /usr/bin,
sometimes not even bash.

Signed-off-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The logic for truncating the log file for emailing based on the
MAIL_MAX_SIZE option is confusing and incorrect. Simplify it and have the
tail of the log file truncated to the max size specified in the config.

Cc: stable@vger.kernel.org
Fixes: 855d8abd2e8ff ("ktest.pl: Change the logic to control the size of the log file emailed")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If the size of the error log is too big to send via email, and the sending
fails, it wont email any result. This can be confusing for the user who is
waiting for an email on the completion of the tests.

If it fails to send email, then try again without the log file stating that
it failed to send an email. Obviously this will not be of use if the sending
of email failed for some other reasons, but it will at least give the user
some information when it fails for the most common reason.

Cc: stable@vger.kernel.org
Fixes: c2d84ddb338c8 ("ktest.pl: Add MAIL_COMMAND option to define how to send email")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

This issue was first noticed when I was testing different kernels on
Oracle Linux 8 which as Fedora 30+ adopts BLS as default. Even though a
kernel entry was added successfully and the index of that kernel entry was
retrieved correctly, ktest still wouldn't reboot the system into
user-specified kernel.

The bug was spotted in subroutine reboot_to where the if-statement never
checks for REBOOT_TYPE "grub2bls", therefore the desired entry will not be
set for the next boot.

Add a check for "grub2bls" so that $grub_reboot $grub_number can
be run before a reboot if REBOOT_TYPE is "grub2bls" then we can boot to
the correct kernel.

Link: https://lkml.kernel.org/r/20201121021243.1532477-1-libo.chen@oracle.com

Cc: stable@vger.kernel.org
Fixes: ac2466456eaa ("ktest: introduce grub2bls REBOOT_TYPE option")
Signed-off-by: Libo Chen <libo.chen@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull ktest updates from Steven Rostedt:

 - Have config-bisect save the good/bad configs at each step.

 - Show log file location even on success

 - Add PRE_TEST_DIE to kill test if the PRE_TEST fails

 - Add a NOT operator for conditionals in config file

 - Add the log output of the last test when emailing on failure.

 - Other minor clean ups and small fixes.

* tag 'ktest-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-ktest:
  ktest.pl: Fix spelling mistake "Cant" -> "Can't"
  ktest.pl: Change the logic to control the size of the log file emailed
  ktest.pl: Add MAIL_MAX_SIZE to limit the amount of log emailed
  ktest.pl: Add the log of last test in email on failure
  ktest.pl: Turn off buffering to the log file
  ktest.pl: Just open up the log file once
  ktest.pl: Add a NOT operator
  ktest.pl: Define PRE_TEST_DIE to kill the test if the PRE_TEST fails
  ktest.pl: Always show log file location if defined even on success
  ktest.pl: Have config-bisect save each config used in the bisect

There is a spelling mistake in an error message. Fix it.

Link: https://lkml.kernel.org/r/20200810100750.61475-1-colin.king@canonical.com

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If the log file for a given test is larger than the max size given then use
set the seek from the end of the log file instead of from the start of the
test.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200726120752.16768-1-grandmaster@al2klimov.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add the ktest config option MAIL_MAX_SIZE that will limit the size of the
log file that is placed into the email on failure.

Link: https://lore.kernel.org/r/20200701231756.790637968@goodmis.org

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>