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Kees Cook 165335d4f1 x86/boot: Fix if_changed build flip/flop bug
[ Upstream commit 92a4728608 ]

Dirk Gouders reported that two consecutive "make" invocations on an
already compiled tree will show alternating behaviors:

$ make
  CALL    scripts/checksyscalls.sh
  DESCEND  objtool
  CHK     include/generated/compile.h
  DATAREL arch/x86/boot/compressed/vmlinux
Kernel: arch/x86/boot/bzImage is ready  (#48)
  Building modules, stage 2.
  MODPOST 165 modules

$ make
  CALL    scripts/checksyscalls.sh
  DESCEND  objtool
  CHK     include/generated/compile.h
  LD      arch/x86/boot/compressed/vmlinux
  ZOFFSET arch/x86/boot/zoffset.h
  AS      arch/x86/boot/header.o
  LD      arch/x86/boot/setup.elf
  OBJCOPY arch/x86/boot/setup.bin
  OBJCOPY arch/x86/boot/vmlinux.bin
  BUILD   arch/x86/boot/bzImage
Setup is 15644 bytes (padded to 15872 bytes).
System is 6663 kB
CRC 3eb90f40
Kernel: arch/x86/boot/bzImage is ready  (#48)
  Building modules, stage 2.
  MODPOST 165 modules

He bisected it back to:

    commit 98f7852537 ("x86/boot: Refuse to build with data relocations")

The root cause was the use of the "if_changed" kbuild function multiple
times for the same target. It was designed to only be used once per
target, otherwise it will effectively always trigger, flipping back and
forth between the two commands getting recorded by "if_changed". Instead,
this patch merges the two commands into a single function to get stable
build artifacts (i.e. .vmlinux.cmd), and a single build behavior.

Bisected-and-Reported-by: Dirk Gouders <dirk@gouders.net>
Fix-Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180724230827.GA37823@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-05 09:26:29 +02:00
arch x86/boot: Fix if_changed build flip/flop bug 2018-09-05 09:26:29 +02:00
block block: sed-opal: Fix a couple off by one bugs 2018-08-24 13:09:03 +02:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: skcipher - fix crash flushing dcache in error path 2018-08-17 21:01:10 +02:00
Documentation kbuild: verify that $DEPMOD is installed 2018-08-17 21:01:10 +02:00
drivers i2c/mux, locking/core: Annotate the nested rt_mutex usage 2018-09-05 09:26:29 +02:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs ext4: clear mmp sequence number when remounting read-only 2018-09-05 09:26:24 +02:00
include locking/rtmutex: Allow specifying a subclass for nested locking 2018-09-05 09:26:29 +02:00
init init: rename and re-order boot_cpu_state_init() 2018-08-15 18:12:48 +02:00
ipc ipc/shm: fix shmat() nil address after round-down when remapping 2018-05-30 07:51:49 +02:00
kernel sched/rt: Restore rt_runtime after disabling RT_RUNTIME_SHARE 2018-09-05 09:26:29 +02:00
lib ioremap: Update pgtable free interfaces with addr 2018-08-17 21:01:11 +02:00
mm kasan: fix shadow_size calculation error in kasan_module_alloc 2018-08-24 13:09:12 +02:00
net net: caif: Add a missing rcu_read_unlock() in caif_flow_cb 2018-09-05 09:26:27 +02:00
samples samples/bpf: Check the error of write() and read() 2018-08-24 13:09:12 +02:00
scripts kconfig: fix line numbers for if-entries in menu tree 2018-08-24 13:09:06 +02:00
security Smack: Mark inode instant in smack_task_to_inode 2018-08-24 13:09:04 +02:00
sound ALSA: seq: Fix UBSAN warning at SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT ioctl 2018-08-24 13:09:05 +02:00
tools tools/power turbostat: fix -S on UP systems 2018-09-05 09:26:27 +02:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer 2018-08-24 13:09:21 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS dt-bindings: Document mti,mips-cpc binding 2018-03-15 10:54:35 +01:00
Makefile Linux 4.14.67 2018-08-24 13:09:23 +02:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.