# git rev-parse -q --verify b6e6cc1f78c772e952495b7416c9ac9029f9390c^{commit}
b6e6cc1f78c772e952495b7416c9ac9029f9390c
already have revision, skipping fetch
# git checkout -q -f -B kisskb b6e6cc1f78c772e952495b7416c9ac9029f9390c
# git clean -qxdf
# < git log -1
# commit b6e6cc1f78c772e952495b7416c9ac9029f9390c
# Merge: be522ac7cdcc 535d0ae39185
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Fri Jul 14 20:19:25 2023 -0700
# 
#     Merge tag 'x86_urgent_for_6.5_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
#     
#     Pull x86 CFI fixes from Peter Zijlstra:
#      "Fix kCFI/FineIBT weaknesses
#     
#       The primary bug Alyssa noticed was that with FineIBT enabled function
#       prologues have a spurious ENDBR instruction:
#     
#         __cfi_foo:
#             endbr64
#             subl    $hash, %r10d
#             jz      1f
#             ud2
#             nop
#         1:
#         foo:
#             endbr64 <--- *sadface*
#     
#       This means that any indirect call that fails to target the __cfi
#       symbol and instead targets (the regular old) foo+0, will succeed due
#       to that second ENDBR.
#     
#       Fixing this led to the discovery of a single indirect call that was
#       still doing this: ret_from_fork(). Since that's an assembly stub the
#       compiler would not generate the proper kCFI indirect call magic and it
#       would not get patched.
#     
#       Brian came up with the most comprehensive fix -- convert the thing to
#       C with only a very thin asm wrapper. This ensures the kernel thread
#       boostrap is a proper kCFI call.
#     
#       While discussing all this, Kees noted that kCFI hashes could/should be
#       poisoned to seal all functions whose address is never taken, further
#       limiting the valid kCFI targets -- much like we already do for IBT.
#     
#       So what was a 'simple' observation and fix cascaded into a bunch of
#       inter-related CFI infrastructure fixes"
#     
#     * tag 'x86_urgent_for_6.5_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
#       x86/cfi: Only define poison_cfi() if CONFIG_X86_KERNEL_IBT=y
#       x86/fineibt: Poison ENDBR at +0
#       x86: Rewrite ret_from_fork() in C
#       x86/32: Remove schedule_tail_wrapper()
#       x86/cfi: Extend ENDBR sealing to kCFI
#       x86/alternative: Rename apply_ibt_endbr()
#       x86/cfi: Extend {JMP,CAKK}_NOSPEC comment
# < /opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 b6e6cc1f78c772e952495b7416c9ac9029f9390c
# make -s -j 40 ARCH=um O=/kisskb/build/linus_allmodconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 allmodconfig
# Added to kconfig CONFIG_STANDALONE=y
# Added to kconfig CONFIG_KCOV=n
# Added to kconfig CONFIG_GCC_PLUGINS=n
# Added to kconfig CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=n
# Added to kconfig CONFIG_GCC_PLUGIN_SANCOV=n
# Added to kconfig CONFIG_GCC_PLUGIN_LATENT_ENTROPY=n
# Added to kconfig CONFIG_GCC_PLUGIN_STRUCTLEAK=n
# Added to kconfig CONFIG_GCC_PLUGIN_RANDSTRUCT=n
# Added to kconfig CONFIG_UML_NET=n
# Added to kconfig CONFIG_UML_NET_ETHERTAP=n
# Added to kconfig CONFIG_UML_NET_TUNTAP=n
# Added to kconfig CONFIG_UML_NET_SLIP=n
# Added to kconfig CONFIG_UML_NET_DAEMON=n
# Added to kconfig CONFIG_UML_NET_VDE=n
# Added to kconfig CONFIG_UML_NET_MCAST=n
# Added to kconfig CONFIG_UML_NET_PCAP=n
# Added to kconfig CONFIG_UML_NET_SLIRP=n
# Added to kconfig CONFIG_GCOV_KERNEL=n
# Added to kconfig CONFIG_DEBUG_INFO_BTF=n
# Added to kconfig CONFIG_BPF_PRELOAD=n
# Added to kconfig CONFIG_SPI_STM32_QSPI=n
# < make -s -j 40 ARCH=um O=/kisskb/build/linus_allmodconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 help
# make -s -j 40 ARCH=um O=/kisskb/build/linus_allmodconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 olddefconfig
.config:12755:warning: override: reassigning to symbol GCC_PLUGIN_LATENT_ENTROPY
.config:12759:warning: override: reassigning to symbol UML_NET_ETHERTAP
.config:12761:warning: override: reassigning to symbol UML_NET_SLIP
.config:12766:warning: override: reassigning to symbol UML_NET_SLIRP
# make -s -j 40 ARCH=um O=/kisskb/build/linus_allmodconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 
  LINK linux
Completed OK
# rm -rf /kisskb/build/linus_allmodconfig_um-x86_64-gcc12
# Build took: 0:09:57.524959