The 'dtbinst_root' is used to remember the root of the in-kernel dts
directory (i.e. arch/*/boot/dts), but it looks clumsy.

I prefer using two variables 'obj' and 'dst' to track the in-kernel
directory and the install destination, respectively.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

gcc-10 will rename --param=allow-store-data-races=0
to -fno-allow-store-data-races.

The flag change happened at https://gcc.gnu.org/PR92046.
Signed-off-by: NSergei Trofimovich <slyfox@gentoo.org>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

The 'imply' statement may create unmet direct dependency when the
implied symbol depends on m.

[Test Code]

  config FOO
          tristate "foo"
          imply BAZ

  config BAZ
          tristate "baz"
          depends on BAR

  config BAR
          def_tristate m

  config MODULES
          def_bool y
          option modules

If you set FOO=y, BAZ is also promoted to y, which results in the
following .config file:

  CONFIG_FOO=y
  CONFIG_BAZ=y
  CONFIG_BAR=m
  CONFIG_MODULES=y

This does not meet the dependency 'BAZ depends on BAR'.

Unlike 'select', what is worse, Kconfig never shows the
'WARNING: unmet direct dependencies detected for ...' for this case.

Because 'imply' is considered to be weaker than 'depends on', Kconfig
should take the direct dependency into account.

For clarification, describe this case in kconfig-language.rst too.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Tested-by: NGeert Uytterhoeven <geert@linux-m68k.org>

The 'imply' keyword restricts a symbol to y or n, excluding m
when it is implied by y. This is the original behavior since
commit 237e3ad0 ("Kconfig: Introduce the "imply" keyword").

However, the author of this feature, Nicolas Pitre, stated that
the 'imply' keyword should not impose any restrictions.
(https://lkml.org/lkml/2020/2/19/714)

I agree, and want to get rid of this tricky behavior.
Suggested-by: NNicolas Pitre <nico@fluxnic.net>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NNicolas Pitre <nico@fluxnic.net>

In net/Kconfig, NET_DEVLINK implies NET_DROP_MONITOR.

The original behavior of the 'imply' keyword prevents NET_DROP_MONITOR
from being 'm' when NET_DEVLINK=y.

With the planned Kconfig change that relaxes the 'imply', the
combination of NET_DEVLINK=y and NET_DROP_MONITOR=m would be allowed.

Use IS_REACHABLE() to avoid the vmlinux link error for this case.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>

Currently when CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, modpost
only warns when a module is missing namespace imports. Under this
configuration, such a module cannot be loaded into the kernel anyway, as
the module loader would reject it. We might as well return a build
error when a module is missing namespace imports under
CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, so that the build
warning does not go ignored/unnoticed.
Signed-off-by: NJessica Yu <jeyu@kernel.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Rework modpost's logging interface by consolidating merror(), warn(), and
fatal() to use a single function, modpost_log(). Introduce different
logging levels (WARN, ERROR, FATAL) as well. The purpose of this cleanup is
to reduce code duplication when deciding whether or not to warn or error
out based on a condition.
Signed-off-by: NJessica Yu <jeyu@kernel.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

The dt_binding_check target is located outside of the
'ifneq ($(dtstree),) ... endif' block.

So, you can run 'make dt_binding_check' on any architecture.
This makes a perfect sense because the dt-schema is arch-agnostic.

The only one problem I see is that scripts/dtc/dtc is not always built.
For example, ARCH=x86 defconfig does not define CONFIG_DTC. Kbuild
descends into scripts/dtc/ with doing nothing. Then, it fails to build
*.example.dt.yaml files.

Let's build scripts/dtc/dtc forcibly when running dt_binding_check.

The dt-schema does not depend on any CONFIG option either, so you
should be able to run dt_binding_check without the .config file.

Going forward, you can directly run 'make dt_binding_check' in a
pristine source tree.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NRob Herring <robh@kernel.org>

Since commit 93512dad ("dt-bindings: Improve validation build error
handling"), 'make dtbs_check' does not validate the schema fully.

If you want to check everything, you need to run two commands separately.

  $ make ARCH=arm dt_binding_check
  $ make ARCH=arm dtbs_check

They are exclusive each other, so you cannot do like this:

  $ make ARCH=arm dt_binding_check dtbs_check

In this case, dt-doc-validate and dt-extract-example are skipped
because CHECK_DTBS is set.

Let's make it possible to run these two targets in a single command.
It will be useful for schema writers.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NRob Herring <robh@kernel.org>

'make dtbs_check' checks the shecma in addition to building *.dtb files,
in other words, 'make dtbs_check' is a super-set of 'make dtbs'.
So, you do not have to do 'make dtbs dtbs_check', but I want to keep
the build system as robust as possible in any use.

Currently, 'dtbs' and 'dtbs_check' are independent of each other.
In parallel building, two threads descend into arch/*/boot/dts/,
one for dtbs and the other for dtbs_check, then end up with building
the same DTB simultaneously.

This commit fixes the concurrency issue. Otherwise, I see build errors
like follows:

$ make ARCH=arm64 defconfig
$ make -j16 ARCH=arm64 DT_SCHEMA_FILES=Documentation/devicetree/bindings/arm/psci.yaml dtbs dtbs_check
  <snip>
  DTC     arch/arm64/boot/dts/qcom/sdm845-cheza-r2.dtb
  DTC     arch/arm64/boot/dts/amlogic/meson-gxl-s905x-p212.dtb
  DTC     arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb
  DTC     arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb
  DTC     arch/arm64/boot/dts/freescale/imx8mn-evk.dtb
  DTC     arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb
  DTC     arch/arm64/boot/dts/zte/zx296718-pcbox.dtb
  DTC     arch/arm64/boot/dts/altera/socfpga_stratix10_socdk.dt.yaml
  DTC     arch/arm64/boot/dts/amlogic/meson-gxl-s905d-p230.dtb
  DTC     arch/arm64/boot/dts/xilinx/zynqmp-zc1254-revA.dtb
  DTC     arch/arm64/boot/dts/allwinner/sun50i-h6-pine-h64.dtb
  DTC     arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet-inx.dtb
  DTC     arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb
  CHECK   arch/arm64/boot/dts/altera/socfpga_stratix10_socdk.dt.yaml
fixdep: error opening file: arch/arm64/boot/dts/allwinner/.sun50i-h6-orangepi-lite2.dtb.d: No such file or directory
make[2]: *** [scripts/Makefile.lib:296: arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb] Error 2
make[2]: *** Deleting file 'arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb'
make[2]: *** Waiting for unfinished jobs....
  DTC     arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet-kd.dtb
  DTC     arch/arm64/boot/dts/amlogic/meson-gxl-s905d-p231.dtb
  DTC     arch/arm64/boot/dts/xilinx/zynqmp-zc1275-revA.dtb
  DTC     arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dtb
fixdep: parse error; no targets found
make[2]: *** [scripts/Makefile.lib:296: arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb] Error 1
make[2]: *** Deleting file 'arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb'
make[1]: *** [scripts/Makefile.build:505: arch/arm64/boot/dts/allwinner] Error 2
make[1]: *** Waiting for unfinished jobs....
  DTC     arch/arm64/boot/dts/renesas/r8a77951-salvator-xs.dtb
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NRob Herring <robh@kernel.org>

Now that we have a separate rule for DT binding examples, we can customize
the dtc options. Let's adjust the dtc warnings to me more strict by
default so the examples get cleaned up as they get converted to schema.

Leaving 'avoid_unnecessary_addr_size' and 'graph_child_address' warnings
disabled as examples tend to be incomplete and they generates a lot of
warnings.
Co-developed-by: NMasahiro Yamada <masahiroy@kernel.org>
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Most folks only run dt_binding_check on the single schema they care about
by setting DT_SCHEMA_FILES. That means example is only checked against
that one schema which is not always sufficient.

Let's address this by splitting processed-schema.yaml into 2 files: one
that's always all schemas for the examples and one that's just the schema
in DT_SCHEMA_FILES for dtbs.
Co-developed-by: NMasahiro Yamada <masahiroy@kernel.org>
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

When doing a cold build, autoksyms.h starts empty, and is updated late
in the build process to have visibility over the symbols used by in-tree
drivers. But since the symbol whitelist is known upfront, it can be used
to pre-populate autoksyms.h and maximize the amount of code that can be
compiled to its final state in a single pass, hence reducing build time.

Do this by using gen_autoksyms.sh to initialize autoksyms.h instead of
creating an empty file.
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Tested-by: NMatthias Maennich <maennich@google.com>
Reviewed-by: NMatthias Maennich <maennich@google.com>
Signed-off-by: NQuentin Perret <qperret@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

In order to prepare the ground for a build-time optimization, split
adjust_autoksyms.sh into two scripts: one that generates autoksyms.h
based on all currently available information (whitelist, and .mod
files), and the other to inspect the diff between two versions of
autoksyms.h and trigger appropriate rebuilds.
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Tested-by: NMatthias Maennich <maennich@google.com>
Reviewed-by: NMatthias Maennich <maennich@google.com>
Signed-off-by: NQuentin Perret <qperret@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

CONFIG_TRIM_UNUSED_KSYMS currently removes all unused exported symbols
from ksymtab. This works really well when using in-tree drivers, but
cannot be used in its current form if some of them are out-of-tree.

Indeed, even if the list of symbols required by out-of-tree drivers is
known at compile time, the only solution today to guarantee these don't
get trimmed is to set CONFIG_TRIM_UNUSED_KSYMS=n. This not only wastes
space, but also makes it difficult to control the ABI usable by vendor
modules in distribution kernels such as Android. Being able to control
the kernel ABI surface is particularly useful to ship a unique Generic
Kernel Image (GKI) for all vendors, which is a first step in the
direction of getting all vendors to contribute their code upstream.

As such, attempt to improve the situation by enabling users to specify a
symbol 'whitelist' at compile time. Any symbol specified in this
whitelist will be kept exported when CONFIG_TRIM_UNUSED_KSYMS is set,
even if it has no in-tree user. The whitelist is defined as a simple
text file, listing symbols, one per line.
Acked-by: NJessica Yu <jeyu@kernel.org>
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Tested-by: NMatthias Maennich <maennich@google.com>
Reviewed-by: NMatthias Maennich <maennich@google.com>
Signed-off-by: NQuentin Perret <qperret@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Most of the Kconfig commands (except defconfig and all*config) read
the .config file as a base set of CONFIG options.

When it does not exist, the files in DEFCONFIG_LIST are searched in
this order and loaded if found.

I do not see much sense in the last two lines in DEFCONFIG_LIST.

[1] ARCH_DEFCONFIG

The entry for DEFCONFIG_LIST is guarded by 'depends on !UML'. So, the
ARCH_DEFCONFIG definition in arch/x86/um/Kconfig is meaningless.

arch/{sh,sparc,x86}/Kconfig define ARCH_DEFCONFIG depending on 32 or
64 bit variant symbols. This is a little bit strange; ARCH_DEFCONFIG
should be a fixed string because the base config file is loaded before
the symbol evaluation stage.

Using KBUILD_DEFCONFIG makes more sense because it is fixed before
Kconfig is invoked. Fortunately, arch/{sh,sparc,x86}/Makefile define it
in the same way, and it works as expected. Hence, replace ARCH_DEFCONFIG
with "arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG)".

[2] arch/$(ARCH)/defconfig

This file path is no longer valid. The defconfig files are always located
in the arch configs/ directories.

  $ find arch -name defconfig | sort
  arch/alpha/configs/defconfig
  arch/arm64/configs/defconfig
  arch/csky/configs/defconfig
  arch/nds32/configs/defconfig
  arch/riscv/configs/defconfig
  arch/s390/configs/defconfig
  arch/unicore32/configs/defconfig

The path arch/*/configs/defconfig is already covered by
"arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG)". So, this file path is
not necessary.

I moved the default KBUILD_DEFCONFIG to the top Makefile. Otherwise,
the 7 architectures listed above would end up with endless loop of
syncconfig.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Added to kbuild documentation. Provides more official info on building
kernels with Clang and LLVM than our wiki.
Suggested-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NSedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

obj-* needs a trailing slash for a directory, but subdir-* does not
because it already implies a directory.

Also, change subdir-y to subdir- to ensure this is effective only
for cleaning targets.

This makes the cleaning log consistent. (no trailing slash)

Before:

  $ make clean
  CLEAN   Documentation/devicetree/bindings/

After:

  $ make clean
  CLEAN   Documentation/devicetree/bindings
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

If *q is '\0', the condition (isalnum(*q) || *q == '_') is false anyway.

It is redundant to ensure non-zero *q.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

This is probably stale code. In old days (~ Linux 2.5.59), Kbuild made
genksyms generate include/linux/modules/*.ver files.

The currenct Kbuild does not generate *.ver files at all.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

This CONFIG option was added by commit 35bb5b1e ("Add option to
enable -Wframe-larger-than= on gcc 4.4"). At that time, the cc-option
check was needed.

According to Documentation/process/changes.rst, the current minimal
supported version of GCC is 4.6, so you can assume GCC supports it.
Clang supports it as well.

Remove the cc-option switch and redundant comments.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>

This reverts a very old commit, which dates back to the pre-git era:

|commit 5d1cfb5b12f72145d30ba0f53c9f238144b122b8
|Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de>
|Date:   Sat Jul 27 02:53:19 2002 -0500
|
|    kbuild: Fix compiling/installing as different users
|
|    "make bzImage && sudo make install" had the problem that during
|    the "sudo make install" the build system would notice that the information
|    in include/linux/compile.h is not accurate (it says "compiled by <user>",
|    but we are root), thus causing compile.h to be updated and leading to
|    some recompiles.
|
|    We now only update "compile.h" if the current user is the owner of
|    include/linux/autoconf.h, i.e. the user who did the "make *config". So the
|    above sequence will correctly state "compiled by <user>".
|
|diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
|index 6313db96172..cd956380978 100755
|--- a/scripts/mkcompile_h
|+++ b/scripts/mkcompile_h
|@@ -3,6 +3,17 @@ ARCH=$2
| SMP=$3
| CC=$4
|
|+# If compile.h exists already and we don't own autoconf.h
|+# (i.e. we're not the same user who did make *config), don't
|+# modify compile.h
|+# So "sudo make install" won't change the "compiled by <user>"
|+# do "compiled by root"
|+
|+if [ -r $TARGET -a ! -O ../include/linux/autoconf.h ]; then
|+  echo ' (not modified)'
|+  exit 0
|+fi
|+
| if [ -r ../.version ]; then
|   VERSION=`cat ../.version`
| else

The 'make bzImage && sudo make install' problem no longer happens
because commit 1648e4f8 ("x86, kbuild: make "make install" not
depend on vmlinux") fixed the root cause.

Commit 19514fc6 ("arm, kbuild: make "make install" not depend on
vmlinux") fixed the similar issue on ARM, with detailed explanation.

So, the rule is that the installation targets should never trigger
the builds of any build artifact. By following it, this check is
unneeded.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Pull ext4 fixes from Ted Ts'o:
 "Two more bug fixes (including a regression) for 5.6"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: potential crash on allocation error in ext4_alloc_flex_bg_array()
  jbd2: fix data races at struct journal_head

Pull KVM fixes from Paolo Bonzini:
 "More bugfixes, including a few remaining "make W=1" issues such as too
  large frame sizes on some configurations.

  On the ARM side, the compiler was messing up shadow stacks between EL1
  and EL2 code, which is easily fixed with __always_inline"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: VMX: check descriptor table exits on instruction emulation
  kvm: x86: Limit the number of "kvm: disabled by bios" messages
  KVM: x86: avoid useless copy of cpufreq policy
  KVM: allow disabling -Werror
  KVM: x86: allow compiling as non-module with W=1
  KVM: Pre-allocate 1 cpumask variable per cpu for both pv tlb and pv ipis
  KVM: Introduce pv check helpers
  KVM: let declaration of kvm_get_running_vcpus match implementation
  KVM: SVM: allocate AVIC data structures based on kvm_amd module parameter
  arm64: Ask the compiler to __always_inline functions used by KVM at HYP
  KVM: arm64: Define our own swab32() to avoid a uapi static inline
  KVM: arm64: Ask the compiler to __always_inline functions used at HYP
  kvm: arm/arm64: Fold VHE entry/exit work into kvm_vcpu_run_vhe()
  KVM: arm/arm64: Fix up includes for trace.h

KVM emulates UMIP on hardware that doesn't support it by setting the
'descriptor table exiting' VM-execution control and performing
instruction emulation. When running nested, this emulation is broken as
KVM refuses to emulate L2 instructions by default.

Correct this regression by allowing the emulation of descriptor table
instructions if L1 hasn't requested 'descriptor table exiting'.

Fixes: 07721fee ("KVM: nVMX: Don't emulate instructions in guest mode")
Reported-by: NJan Kiszka <jan.kiszka@web.de>
Cc: stable@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Pull i2c fixes from Wolfram Sang:
 "I2C has three driver bugfixes for you. We agreed on the Mac regression
  to go in via I2C"

* 'i2c/for-current-fixed' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  macintosh: therm_windtunnel: fix regression when instantiating devices
  i2c: altera: Fix potential integer overflow
  i2c: jz4780: silence log flood on txabrt

If sbi->s_flex_groups_allocated is zero and the first allocation fails
then this code will crash.  The problem is that "i--" will set "i" to
-1 but when we compare "i >= sbi->s_flex_groups_allocated" then the -1
is type promoted to unsigned and becomes UINT_MAX.  Since UINT_MAX
is more than zero, the condition is true so we call kvfree(new_groups[-1]).
The loop will carry on freeing invalid memory until it crashes.

Fixes: 7c990728 ("ext4: fix potential race between s_flex_groups online resizing and access")
Reviewed-by: NSuraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20200228092142.7irbc44yaz3by7nb@kili.mountainSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Removing attach_adapter from this driver caused a regression for at
least some machines. Those machines had the sensors described in their
DT, too, so they didn't need manual creation of the sensor devices. The
old code worked, though, because manual creation came first. Creation of
DT devices then failed later and caused error logs, but the sensors
worked nonetheless because of the manually created devices.

When removing attach_adaper, manual creation now comes later and loses
the race. The sensor devices were already registered via DT, yet with
another binding, so the driver could not be bound to it.

This fix refactors the code to remove the race and only manually creates
devices if there are no DT nodes present. Also, the DT binding is updated
to match both, the DT and manually created devices. Because we don't
know which device creation will be used at runtime, the code to start
the kthread is moved to do_probe() which will be called by both methods.

Fixes: 3e7bed52 ("macintosh: therm_windtunnel: drop using attach_adapter")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201723Reported-by: NErhard Furtner <erhard_f@mailbox.org>
Tested-by: NErhard Furtner <erhard_f@mailbox.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org # v4.19+

journal_head::b_transaction and journal_head::b_next_transaction could
be accessed concurrently as noticed by KCSAN,

 LTP: starting fsync04
 /dev/zero: Can't open blockdev
 EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem
 EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: (null)
 ==================================================================
 BUG: KCSAN: data-race in __jbd2_journal_refile_buffer [jbd2] / jbd2_write_access_granted [jbd2]

 write to 0xffff99f9b1bd0e30 of 8 bytes by task 25721 on cpu 70:
  __jbd2_journal_refile_buffer+0xdd/0x210 [jbd2]
  __jbd2_journal_refile_buffer at fs/jbd2/transaction.c:2569
  jbd2_journal_commit_transaction+0x2d15/0x3f20 [jbd2]
  (inlined by) jbd2_journal_commit_transaction at fs/jbd2/commit.c:1034
  kjournald2+0x13b/0x450 [jbd2]
  kthread+0x1cd/0x1f0
  ret_from_fork+0x27/0x50

 read to 0xffff99f9b1bd0e30 of 8 bytes by task 25724 on cpu 68:
  jbd2_write_access_granted+0x1b2/0x250 [jbd2]
  jbd2_write_access_granted at fs/jbd2/transaction.c:1155
  jbd2_journal_get_write_access+0x2c/0x60 [jbd2]
  __ext4_journal_get_write_access+0x50/0x90 [ext4]
  ext4_mb_mark_diskspace_used+0x158/0x620 [ext4]
  ext4_mb_new_blocks+0x54f/0xca0 [ext4]
  ext4_ind_map_blocks+0xc79/0x1b40 [ext4]
  ext4_map_blocks+0x3b4/0x950 [ext4]
  _ext4_get_block+0xfc/0x270 [ext4]
  ext4_get_block+0x3b/0x50 [ext4]
  __block_write_begin_int+0x22e/0xae0
  __block_write_begin+0x39/0x50
  ext4_write_begin+0x388/0xb50 [ext4]
  generic_perform_write+0x15d/0x290
  ext4_buffered_write_iter+0x11f/0x210 [ext4]
  ext4_file_write_iter+0xce/0x9e0 [ext4]
  new_sync_write+0x29c/0x3b0
  __vfs_write+0x92/0xa0
  vfs_write+0x103/0x260
  ksys_write+0x9d/0x130
  __x64_sys_write+0x4c/0x60
  do_syscall_64+0x91/0xb05
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

 5 locks held by fsync04/25724:
  #0: ffff99f9911093f8 (sb_writers#13){.+.+}, at: vfs_write+0x21c/0x260
  #1: ffff99f9db4c0348 (&sb->s_type->i_mutex_key#15){+.+.}, at: ext4_buffered_write_iter+0x65/0x210 [ext4]
  #2: ffff99f5e7dfcf58 (jbd2_handle){++++}, at: start_this_handle+0x1c1/0x9d0 [jbd2]
  #3: ffff99f9db4c0168 (&ei->i_data_sem){++++}, at: ext4_map_blocks+0x176/0x950 [ext4]
  #4: ffffffff99086b40 (rcu_read_lock){....}, at: jbd2_write_access_granted+0x4e/0x250 [jbd2]
 irq event stamp: 1407125
 hardirqs last  enabled at (1407125): [<ffffffff980da9b7>] __find_get_block+0x107/0x790
 hardirqs last disabled at (1407124): [<ffffffff980da8f9>] __find_get_block+0x49/0x790
 softirqs last  enabled at (1405528): [<ffffffff98a0034c>] __do_softirq+0x34c/0x57c
 softirqs last disabled at (1405521): [<ffffffff97cc67a2>] irq_exit+0xa2/0xc0

 Reported by Kernel Concurrency Sanitizer on:
 CPU: 68 PID: 25724 Comm: fsync04 Tainted: G L 5.6.0-rc2-next-20200221+ #7
 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019

The plain reads are outside of jh->b_state_lock critical section which result
in data races. Fix them by adding pairs of READ|WRITE_ONCE().
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NQian Cai <cai@lca.pw>
Link: https://lore.kernel.org/r/20200222043111.2227-1-cai@lca.pwSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Pull SCSI fixes from James Bottomley:
 "Four small fixes.

  Three are in drivers for fairly obvious bugs. The fourth is a set of
  regressions introduced by the compat_ioctl changes because some of the
  compat updates wrongly replaced .ioctl instead of .compat_ioctl"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: compat_ioctl: cdrom: Replace .ioctl with .compat_ioctl in four appropriate places
  scsi: zfcp: fix wrong data and display format of SFP+ temperature
  scsi: sd_sbc: Fix sd_zbc_report_zones()
  scsi: libfc: free response frame from GPN_ID

Pull PCI fixes from Bjorn Helgaas:

 - Fix build issue on 32-bit ARM with old compilers (Marek Szyprowski)

 - Update MAINTAINERS for recent Cadence driver file move (Lukas
   Bulwahn)

* tag 'pci-v5.6-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  MAINTAINERS: Correct Cadence PCI driver path
  PCI: brcmstb: Fix build on 32bit ARM platforms with older compilers

Pull block fixes from Jens Axboe:

 - Passthrough insertion fix (Ming)

 - Kill off some unused arguments (John)

 - blktrace RCU fix (Jan)

 - Dead fields removal for null_blk (Dongli)

 - NVMe polled IO fix (Bijan)

* tag 'block-5.6-2020-02-28' of git://git.kernel.dk/linux-block:
  nvme-pci: Hold cq_poll_lock while completing CQEs
  blk-mq: Remove some unused function arguments
  null_blk: remove unused fields in 'nullb_cmd'
  blktrace: Protect q->blk_trace with RCU
  blk-mq: insert passthrough request into hctx->dispatch directly

Pull io_uring fixes from Jens Axboe:

 - Fix for a race with IOPOLL used with SQPOLL (Xiaoguang)

 - Only show ->fdinfo if procfs is enabled (Tobias)

 - Fix for a chain with multiple personalities in the SQEs

 - Fix for a missing free of personality idr on exit

 - Removal of the spin-for-work optimization

 - Fix for next work lookup on request completion

 - Fix for non-vec read/write result progation in case of links

 - Fix for a fileset references on switch

 - Fix for a recvmsg/sendmsg 32-bit compatability mode

* tag 'io_uring-5.6-2020-02-28' of git://git.kernel.dk/linux-block:
  io_uring: fix 32-bit compatability with sendmsg/recvmsg
  io_uring: define and set show_fdinfo only if procfs is enabled
  io_uring: drop file set ref put/get on switch
  io_uring: import_single_range() returns 0/-ERROR
  io_uring: pick up link work on submit reference drop
  io-wq: ensure work->task_pid is cleared on init
  io-wq: remove spin-for-work optimization
  io_uring: fix poll_list race for SETUP_IOPOLL|SETUP_SQPOLL
  io_uring: fix personality idr leak
  io_uring: handle multiple personalities in link chains

Pull NVMe fix from Keith.

* 'nvme-5.6-rc4' of git://git.infradead.org/nvme:
  nvme-pci: Hold cq_poll_lock while completing CQEs

Pull ACPI fixes from Rafael Wysocki:
 "Fix a couple of configuration issues in the ACPI watchdog (WDAT)
  driver (Mika Westerberg) and make it possible to disable that driver
  at boot time in case it still does not work as expected (Jean
  Delvare)"

* tag 'acpi-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: watchdog: Set default timeout in probe
  ACPI: watchdog: Fix gas->access_width usage
  ACPICA: Introduce ACPI_ACCESS_BYTE_WIDTH() macro
  ACPI: watchdog: Allow disabling WDAT at boot

Pull power management fixes from Rafael Wysocki:
 "Fix a recent cpufreq initialization regression (Rafael Wysocki),
  revert a devfreq commit that made incompatible changes and broke user
  land on some systems (Orson Zhai), drop a stale reference to a
  document that has gone away recently (Jonathan Neuschäfer), and fix a
  typo in a hibernation code comment (Alexandre Belloni)"

* tag 'pm-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: Fix policy initialization for internal governor drivers
  Revert "PM / devfreq: Modify the device name as devfreq(X) for sysfs"
  PM / hibernate: fix typo "reserverd_size" -> "reserved_size"
  Documentation: power: Drop reference to interface.rst

Pull zonefs fixes from Damien Le Moal:
 "Two fixes in here:

   - Revert the initial decision to silently ignore IOCB_NOWAIT for
     asynchronous direct IOs to sequential zone files. Instead, return
     an error to the user to signal that the feature is not supported
     (from Christoph)

   - A fix to zonefs Kconfig to select FS_IOMAP to avoid build failures
     if no other file system already selected this option (from
     Johannes)"

* tag 'zonefs-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: select FS_IOMAP
  zonefs: fix IOCB_NOWAIT handling

Merge tag 'kvmarm-fixes-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm fixes for 5.6, take #1

- Fix compilation on 32bit
- Move  VHE guest entry/exit into the VHE-specific entry code
- Make sure all functions called by the non-VHE HYP code is tagged as __always_inline

In older version of systemd(219), at boot time, udevadm is called with :
	/usr/bin/udevadm trigger --type=devices --action=add"

This program generates an echo "add" in /sys/devices/system/cpu/cpu<x>/uevent,
leading to the "kvm: disabled by bios" message in case of your Bios disabled
the virtualization extensions.

On a modern system running up to 256 CPU threads, this pollutes the Kernel logs.

This patch offers to ratelimit this message to avoid any userspace program triggering
this uevent printing this message too often.

This patch is only a workaround but greatly reduce the pollution without
breaking the current behavior of printing a message if some try to instantiate
KVM on a system that doesn't support it.

Note that recent versions of systemd (>239) do not have trigger this behavior.

This patch will be useful at least for some using older systemd with recent Kernels.
Signed-off-by: NErwan Velu <e.velu@criteo.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>