MIPS64 little endian target has an odd encoding of r_info.

This commit makes the special handling less ugly. It is still ugly,
but #if conditionals will go away, at least.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

All of addend_*_rel() need the Elf_Rela pointer just for calculating
ELF_R_TYPE(r->r_info).

You can do it on the caller to de-duplicate the code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Now that none of addend_*_rel() returns a meaningful value (the return
value is always 0), change all of them to return the value of r_addend.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Commit 8818039f ("kbuild: add ability to make source rpm buildable
using koji") added the BuildRequires: field.

Checking the build dependency is fine, but one annoyance is that
'make (bin)rpm-pkg' fails on non-rpm systems [1]. For example, Debian
provides rpmbuild via 'apt install rpm', but of course cannot meet the
requirement listed in the BuildRequires: field.

It is possible to pass RPMOPTS=--nodeps to work around it, but it is
reasonable to do it automatically.

If 'rpm -q rpm' fails, it is not an RPM-managed system. (The command
'rpm' is not installed at all, or was installed by other means.)

In that case, pass --nodeps to skip the build dependency check.

[1]: https://lore.kernel.org/linux-kbuild/Y6mkdYQYmjUz7bqV@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com/Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Merge the similar build targets.

Also, make the output location consistent.

Previously, source packages were created in the build directory,
while binary packages under ~/rpmbuild/RPMS/.

Now, Kbuild creates the rpmbuild/ directory in the build directory,
and saves all packages under it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, 'make rpm-pkg' always builds the kernel from the pristine
source tree in the ~/rpmbuild/BUILD/ directory.

Build the kernel incrementally just like 'make binrpm-pkg'.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Now kernel.spec and binkernel.spec have the exactly same contents.

Use kernel.spec for binrpm-pkg as well.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Most of the lines in the spec file are independent of any build
condition.

Split the body of the spec file into scripts/package/kernel.spec.
scripts/package/mkspec will prepend some env-dependent variables.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/package/mkspec preprocesses the spec file by sed, but it is
unreadable. This commit removes the last portion of the sed scripting.

Remove the $S$M prefixes from the conditionally generated lines.
Instead, surround the code with %if %{with_devel} ... %endif.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

For the same reason as commit 4243afdb ("kbuild: builddeb: always
make modules_install, to install modules.builtin*"), run modules_install
even when CONFIG_MODULES=n to install modules.builtin*.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

To reduce the preprocess of the spec file, invoke the kernel build
from rpmbuild.

Run init/build-version to increment the release number not only for
binrpm-pkg but also for srcrpm-pkg and rpm-pkg.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

If this affects only %{buildroot}, it should be enough to use a fixed
string for _arch when it is undefined.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Avoid hard-coding the Version field in the generated spec file.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The kernel-devel RPM package and the linux-headers Debian package
provide headers and scripts needed for building external modules.

They copy the necessary files in slightly different ways - the RPM
copies almost everything except some exclude patterns, while the Debian
copies less number of files. There is no need to maintain different code
to do the same thing.

Split the Debian code out to scripts/package/install-extmod-build, which
is called from both of the packages.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

There are some cases where we want to run a command with the same
environment variables as Kbuild uses. For example, 'make coccicheck'
invokes scripts/coccicheck from the top Makefile so that the script can
reference to ${LINUXINCLUDE}, ${KBUILD_EXTMOD}, etc. The top Makefile
defines several phony targets that run a script.

We do it also for an internally used script, which results in a somewhat
complex call graph.

One example:

 debian/rules binary-arch
   -> make intdeb-pkg
      -> scripts/package/builddeb

It is also tedious to add a dedicated target like 'intdeb-pkg' for each
use case.

Add a generic target 'run-command' to run an arbitrary command in an
environment with all Kbuild variables set.

The usage is:

  $ make run-command KBUILD_RUN_COMMAND=<command>

The concept is similar to:

  $ dpkg-architecture -c <command>

This executes <command> in an environment which has all DEB_* variables
defined.

Convert the existing 'make intdeb-pkg'.

Another possible usage is to interrogate a Make variable.

  $ make run-command KBUILD_RUN_COMMAND='echo $(KBUILD_CFLAGS)'

might be useful to see KBUILD_CFLAGS set by the top Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Avoid hard-coding the value of KERNELRELEASE in the generated spec file.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

${version} will be replaced with the value of the Version field.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, we rely on the top Makefile defining ARCH option when we
run 'make rpm-pkg' or 'make binrpm-pkg'.

It does not apply when we run 'make srcrpm-pkg', and separately run
'rpmbuild' for the generated SRPM. This is a problem for cross-build.

Just like the Debian package, save the value of ARCH in the spec file.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This is useful to pass more common Make options.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, $MAKE will expand to the GNU Make program that created the
source RPM. This is problematic if you carry it to a different build
host to run 'rpmbuild' there.

Consider this command:

  $ /path/to/my/custom/make srcrpm-pkg

The spec file in the SRPM will record '/path/to/my/custom/make', which
exists only on that build environment.

To create a portable SRPM, the spec file should avoid hard-coding $MAKE.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This is unneeded because the Makefile in the output directory wraps
the top-level Makefile in the srctree.

Just run $MAKE irrespective of the build location.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Commit 3089b2be ("kbuild: rpm-pkg: fix build error when _arch is
undefined") does not work as intended; _arch is always defined as
$UTS_MACHINE.

The intention was to define _arch to $UTS_MACHINE only when it is not
defined.

Fixes: 3089b2be ("kbuild: rpm-pkg: fix build error when _arch is undefined")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Remove hack for ancient version of module-init-tools that was added in
Linux 3.0.

Since then module-init-tools was replaced with kmod.

This hack adds an additional indirection, and causes confusing errors
to be printed when depmod fails.

Reverts commit 8fc62e59 ("kbuild: Do not write to builddir in modules_install")
Reverts commit bfe5424a ("kbuild: Hack for depmod not handling X.Y versions")

Link: https://lore.kernel.org/linux-modules/CAK7LNAQMs3QBYfWcLkmOQdbbq7cj=7wWbK=AWhdTC2rAsKHXzQ@mail.gmail.com/Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

You do not need to remember the index of each jump key because you can
count it up after a key is pressed.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jesse Taube <Mr.Bossman075@gmail.com>

Commit 95ac9b3b ("menuconfig: Assign jump keys per-page instead
of globally") injected a lot of hacks to the bottom of the textbox
infrastructure.

I reverted many of them without changing the behavior. (almost)
Now, the key markers are inserted when constructing the search result
instead of updating the text buffer on-the-fly.

The buffer passed to the textbox got back to a constant string.
The ugly casts from (const char *) to (char *) went away.

A disadvantage is that the same key numbers might be displayed multiple
times in the dialog if you use a huge window (but I believe it is
unlikely to happen).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jesse Taube <Mr.Bossman075@gmail.com>

Currently, all files with EXPORT_SYMBOL() are rebuilt when CONFIG_MODULES
is flipped due to <linux/export.h> depending on CONFIG_MODULES.

Now that modpost can make a final decision about export symbols,
<linux/export.h> does not need to make EXPORT_SYMBOL() no-op.
Instead, modpost can skip emitting KSYMTAB when CONFIG_MODULES is unset.

This commit will reduce the number of recompilation when CONFIG_MODULES
is toggled.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This diagnostic checks whether there is a type mismatch when
converting enums (assign an enum of type A to an enum of type B, for
example) and it caught a legit issue recently. The reason it didn't show
is because that warning is enabled only with -Wextra with GCC. Clang,
however, enables it by default.

GCC folks were considering enabling it by default but it was too noisy
back then:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78736

Now that due to clang all those warnings have been fixed, enable it with
GCC too.

allmodconfig tests done with: x86, arm{,64}, powerpc{,64}, riscv
crossbuilds.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Pull tracing fixes from Steven Rostedt:

 - Swapping the ring buffer for snapshotting (for things like irqsoff)
   can crash if the ring buffer is being resized. Disable swapping when
   this happens. The missed swap will be reported to the tracer

 - Report error if the histogram fails to be created due to an error in
   adding a histogram variable, in event_hist_trigger_parse()

 - Remove unused declaration of tracing_map_set_field_descr()

* tag 'trace-v6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/histograms: Return an error if we fail to add histogram to hist_vars list
  ring-buffer: Do not swap cpu_buffer during resize process
  tracing: Remove unused extern declaration tracing_map_set_field_descr()

Merge tag 'kbuild-fixes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix stale help text in gconfig

 - Support *.S files in compile_commands.json

 - Flatten KBUILD_CFLAGS

 - Fix external module builds with Rust so that temporary files are
   created in the modules directories instead of the kernel tree

* tag 'kbuild-fixes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: rust: avoid creating temporary files
  kbuild: flatten KBUILD_CFLAGS
  gen_compile_commands: add assembly files to compilation database
  kconfig: gconfig: correct program name in help text
  kconfig: gconfig: drop the Show Debug Info help text

`rustc` outputs by default the temporary files (i.e. the ones saved
by `-Csave-temps`, such as `*.rcgu*` files) in the current working
directory when `-o` and `--out-dir` are not given (even if
`--emit=x=path` is given, i.e. it does not use those for temporaries).

Since out-of-tree modules are compiled from the `linux` tree,
`rustc` then tries to create them there, which may not be accessible.

Thus pass `--out-dir` explicitly, even if it is just for the temporary
files.

Similarly, do so for Rust host programs too.
Reported-by: Raphael Nestler <raphael.nestler@gmail.com>
Closes: https://github.com/Rust-for-Linux/linux/issues/1015Reported-by: Andrea Righi <andrea.righi@canonical.com>
Tested-by: Raphael Nestler <raphael.nestler@gmail.com> # non-hostprogs
Tested-by: Andrea Righi <andrea.righi@canonical.com> # non-hostprogs
Fixes: 295d8398 ("kbuild: specify output names separately for each emission type from rustc")
Cc: stable@vger.kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Pull kvm fixes from Paolo Bonzini:
 "ARM:

   - Avoid pKVM finalization if KVM initialization fails

   - Add missing BTI instructions in the hypervisor, fixing an early
     boot failure on BTI systems

   - Handle MMU notifiers correctly for non hugepage-aligned memslots

   - Work around a bug in the architecture where hypervisor timer
     controls have UNKNOWN behavior under nested virt

   - Disable preemption in kvm_arch_hardware_enable(), fixing a kernel
     BUG in cpu hotplug resulting from per-CPU accessor sanity checking

   - Make WFI emulation on GICv4 systems robust w.r.t. preemption,
     consistently requesting a doorbell interrupt on vcpu_put()

   - Uphold RES0 sysreg behavior when emulating older PMU versions

   - Avoid macro expansion when initializing PMU register names,
     ensuring the tracepoints pretty-print the sysreg

  s390:

   - Two fixes for asynchronous destroy

  x86 fixes will come early next week"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: s390: pv: fix index value of replaced ASCE
  KVM: s390: pv: simplify shutdown and fix race
  KVM: arm64: Fix the name of sys_reg_desc related to PMU
  KVM: arm64: Correctly handle RES0 bits PMEVTYPER<n>_EL0.evtCount
  KVM: arm64: vgic-v4: Make the doorbell request robust w.r.t preemption
  KVM: arm64: Add missing BTI instructions
  KVM: arm64: Correctly handle page aging notifiers for unaligned memslot
  KVM: arm64: Disable preemption in kvm_arch_hardware_enable()
  KVM: arm64: Handle kvm_arm_init failure correctly in finalize_pkvm
  KVM: arm64: timers: Use CNTHCTL_EL2 when setting non-CNTKCTL_EL1 bits

Pull ext4 fixes from Ted Ts'o:
 "Bug and regression fixes for 6.5-rc3 for ext4's mballoc and jbd2's
  checkpoint code"

* tag 'ext4_for_linus-6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix rbtree traversal bug in ext4_mb_use_preallocated
  ext4: fix off by one issue in ext4_mb_choose_next_group_best_avail()
  ext4: correct inline offset when handling xattrs in inode body
  jbd2: remove __journal_try_to_free_buffer()
  jbd2: fix a race when checking checkpoint buffer busy
  jbd2: Fix wrongly judgement for buffer head removing while doing checkpoint
  jbd2: remove journal_clean_one_cp_list()
  jbd2: remove t_checkpoint_io_list
  jbd2: recheck chechpointing non-dirty buffer

Pull smb client fix from Steve French:
 "Add minor debugging improvement.

  The change improves ability to read a network trace to debug problems
  on encrypted connections which are very common (e.g. using wireshark
  or tcpdump).

  That works today with tools like 'smbinfo keys /mnt/file' but requires
  passing in a filename on the mount (see e.g. [1]), but it often makes
  more sense to just pass in the mount point path (ie a directory not a
  filename).

  So this fix was needed to debug some types of problems (an obvious
  example is on an encrypted connection failing operations on an empty
  share or with no files in the root of the directory) - so you can
  simply pass in the 'smbinfo keys <mntpoint>' and get the information
  that wireshark needs"

Link: https://wiki.samba.org/index.php/Wireshark_Decryption [1]

* tag '6.5-rc2-smb3-client-fixes-ver2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update internal module version number for cifs.ko
  cifs: allow dumping keys for directories too

Merge tag 'kvm-s390-master-6.5-1' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

Two fixes for asynchronous destroy

Merge tag 'kvmarm-fixes-6.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.5, part #1

 - Avoid pKVM finalization if KVM initialization fails

 - Add missing BTI instructions in the hypervisor, fixing an early boot
   failure on BTI systems

 - Handle MMU notifiers correctly for non hugepage-aligned memslots

 - Work around a bug in the architecture where hypervisor timer controls
   have UNKNOWN behavior under nested virt.

 - Disable preemption in kvm_arch_hardware_enable(), fixing a kernel BUG
   in cpu hotplug resulting from per-CPU accessor sanity checking.

 - Make WFI emulation on GICv4 systems robust w.r.t. preemption,
   consistently requesting a doorbell interrupt on vcpu_put()

 - Uphold RES0 sysreg behavior when emulating older PMU versions

 - Avoid macro expansion when initializing PMU register names, ensuring
   the tracepoints pretty-print the sysreg.

Commit 6018b585 ("tracing/histograms: Add histograms to hist_vars if
they have referenced variables") added a check to fail histogram creation
if save_hist_vars() failed to add histogram to hist_vars list. But the
commit failed to set ret to failed return code before jumping to
unregister histogram, fix it.

Link: https://lore.kernel.org/linux-trace-kernel/20230714203341.51396-1-mkhalfella@purestorage.com

Cc: stable@vger.kernel.org
Fixes: 6018b585 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables")
Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

When ring_buffer_swap_cpu was called during resize process,
the cpu buffer was swapped in the middle, resulting in incorrect state.
Continuing to run in the wrong state will result in oops.

This issue can be easily reproduced using the following two scripts:
/tmp # cat test1.sh
//#! /bin/sh
for i in `seq 0 100000`
do
         echo 2000 > /sys/kernel/debug/tracing/buffer_size_kb
         sleep 0.5
         echo 5000 > /sys/kernel/debug/tracing/buffer_size_kb
         sleep 0.5
done
/tmp # cat test2.sh
//#! /bin/sh
for i in `seq 0 100000`
do
        echo irqsoff > /sys/kernel/debug/tracing/current_tracer
        sleep 1
        echo nop > /sys/kernel/debug/tracing/current_tracer
        sleep 1
done
/tmp # ./test1.sh &
/tmp # ./test2.sh &

A typical oops log is as follows, sometimes with other different oops logs.

[  231.711293] WARNING: CPU: 0 PID: 9 at kernel/trace/ring_buffer.c:2026 rb_update_pages+0x378/0x3f8
[  231.713375] Modules linked in:
[  231.714735] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G        W          6.5.0-rc1-00276-g20edcec2 #15
[  231.716750] Hardware name: linux,dummy-virt (DT)
[  231.718152] Workqueue: events update_pages_handler
[  231.719714] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  231.721171] pc : rb_update_pages+0x378/0x3f8
[  231.722212] lr : rb_update_pages+0x25c/0x3f8
[  231.723248] sp : ffff800082b9bd50
[  231.724169] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000
[  231.726102] x26: 0000000000000001 x25: fffffffffffff010 x24: 0000000000000ff0
[  231.728122] x23: ffff0000c3a0b600 x22: ffff0000c3a0b5c0 x21: fffffffffffffe0a
[  231.730203] x20: ffff0000c3a0b600 x19: ffff0000c0102400 x18: 0000000000000000
[  231.732329] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffe7aa8510
[  231.734212] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000002
[  231.736291] x11: ffff8000826998a8 x10: ffff800082b9baf0 x9 : ffff800081137558
[  231.738195] x8 : fffffc00030e82c8 x7 : 0000000000000000 x6 : 0000000000000001
[  231.740192] x5 : ffff0000ffbafe00 x4 : 0000000000000000 x3 : 0000000000000000
[  231.742118] x2 : 00000000000006aa x1 : 0000000000000001 x0 : ffff0000c0007208
[  231.744196] Call trace:
[  231.744892]  rb_update_pages+0x378/0x3f8
[  231.745893]  update_pages_handler+0x1c/0x38
[  231.746893]  process_one_work+0x1f0/0x468
[  231.747852]  worker_thread+0x54/0x410
[  231.748737]  kthread+0x124/0x138
[  231.749549]  ret_from_fork+0x10/0x20
[  231.750434] ---[ end trace 0000000000000000 ]---
[  233.720486] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  233.721696] Mem abort info:
[  233.721935]   ESR = 0x0000000096000004
[  233.722283]   EC = 0x25: DABT (current EL), IL = 32 bits
[  233.722596]   SET = 0, FnV = 0
[  233.722805]   EA = 0, S1PTW = 0
[  233.723026]   FSC = 0x04: level 0 translation fault
[  233.723458] Data abort info:
[  233.723734]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[  233.724176]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[  233.724589]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[  233.725075] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000104943000
[  233.725592] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
[  233.726231] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
[  233.726720] Modules linked in:
[  233.727007] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G        W          6.5.0-rc1-00276-g20edcec2 #15
[  233.727777] Hardware name: linux,dummy-virt (DT)
[  233.728225] Workqueue: events update_pages_handler
[  233.728655] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  233.729054] pc : rb_update_pages+0x1a8/0x3f8
[  233.729334] lr : rb_update_pages+0x154/0x3f8
[  233.729592] sp : ffff800082b9bd50
[  233.729792] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000
[  233.730220] x26: 0000000000000000 x25: ffff800082a8b840 x24: ffff0000c0102418
[  233.730653] x23: 0000000000000000 x22: fffffc000304c880 x21: 0000000000000003
[  233.731105] x20: 00000000000001f4 x19: ffff0000c0102400 x18: ffff800082fcbc58
[  233.731727] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000001
[  233.732282] x14: ffff8000825fe0c8 x13: 0000000000000001 x12: 0000000000000000
[  233.732709] x11: ffff8000826998a8 x10: 0000000000000ae0 x9 : ffff8000801b760c
[  233.733148] x8 : fefefefefefefeff x7 : 0000000000000018 x6 : ffff0000c03298c0
[  233.733553] x5 : 0000000000000002 x4 : 0000000000000000 x3 : 0000000000000000
[  233.733972] x2 : ffff0000c3a0b600 x1 : 0000000000000000 x0 : 0000000000000000
[  233.734418] Call trace:
[  233.734593]  rb_update_pages+0x1a8/0x3f8
[  233.734853]  update_pages_handler+0x1c/0x38
[  233.735148]  process_one_work+0x1f0/0x468
[  233.735525]  worker_thread+0x54/0x410
[  233.735852]  kthread+0x124/0x138
[  233.736064]  ret_from_fork+0x10/0x20
[  233.736387] Code: 92400000 910006b5 aa000021 aa0303f7 (f9400060)
[  233.736959] ---[ end trace 0000000000000000 ]---

After analysis, the seq of the error is as follows [1-5]:

int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
			int cpu_id)
{
	for_each_buffer_cpu(buffer, cpu) {
		cpu_buffer = buffer->buffers[cpu];
		//1. get cpu_buffer, aka cpu_buffer(A)
		...
		...
		schedule_work_on(cpu,
		 &cpu_buffer->update_pages_work);
		//2. 'update_pages_work' is queue on 'cpu', cpu_buffer(A) is passed to
		// update_pages_handler, do the update process, set 'update_done' in
		// complete(&cpu_buffer->update_done) and to wakeup resize process.
	//---->
		//3. Just at this moment, ring_buffer_swap_cpu is triggered,
		//cpu_buffer(A) be swaped to cpu_buffer(B), the max_buffer.
		//ring_buffer_swap_cpu is called as the 'Call trace' below.

		Call trace:
		 dump_backtrace+0x0/0x2f8
		 show_stack+0x18/0x28
		 dump_stack+0x12c/0x188
		 ring_buffer_swap_cpu+0x2f8/0x328
		 update_max_tr_single+0x180/0x210
		 check_critical_timing+0x2b4/0x2c8
		 tracer_hardirqs_on+0x1c0/0x200
		 trace_hardirqs_on+0xec/0x378
		 el0_svc_common+0x64/0x260
		 do_el0_svc+0x90/0xf8
		 el0_svc+0x20/0x30
		 el0_sync_handler+0xb0/0xb8
		 el0_sync+0x180/0x1c0
	//<----

	/* wait for all the updates to complete */
	for_each_buffer_cpu(buffer, cpu) {
		cpu_buffer = buffer->buffers[cpu];
		//4. get cpu_buffer, cpu_buffer(B) is used in the following process,
		//the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong.
		//for example, cpu_buffer(A)->update_done will leave be set 1, and will
		//not 'wait_for_completion' at the next resize round.
		  if (!cpu_buffer->nr_pages_to_update)
			continue;

		if (cpu_online(cpu))
			wait_for_completion(&cpu_buffer->update_done);
		cpu_buffer->nr_pages_to_update = 0;
	}
	...
}
	//5. the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong,
	//Continuing to run in the wrong state, then oops occurs.

Link: https://lore.kernel.org/linux-trace-kernel/202307191558478409990@zte.com.cnSigned-off-by: Chen Lin <chen.lin5@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Since commit 08d43a5f ("tracing: Add lock-free tracing_map"),
this is never used, so can be removed.

Link: https://lore.kernel.org/linux-trace-kernel/20230722032123.24664-1-yuehaibing@huawei.com

Cc: <mhiramat@kernel.org>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Make it slightly easier to see which compiler options are added and
removed (and not worry about column limit too!).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>