# git rev-parse -q --verify f460772291f8171988b2b60141a45706123d0c69^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test
error: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

warning: There are too many unreachable loose objects; run 'git prune' to remove them.

# git rev-parse -q --verify f460772291f8171988b2b60141a45706123d0c69^{commit}
f460772291f8171988b2b60141a45706123d0c69
# git checkout -q -f -B kisskb f460772291f8171988b2b60141a45706123d0c69
# git clean -qxdf
# < git log -1
# commit f460772291f8171988b2b60141a45706123d0c69
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Sun Dec 30 14:05:13 2018 +1100
# 
#     KVM: PPC: Book3S HV: radix: Fix uninitialized var build error
#     
#     Old GCCs (4.6.3 at least), aren't able to follow the logic in
#     __kvmhv_copy_tofrom_guest_radix() and warn that old_pid is used
#     uninitialized:
#     
#       arch/powerpc/kvm/book3s_64_mmu_radix.c:75:3: error: 'old_pid' may be
#       used uninitialized in this function
#     
#     The logic is OK, we only use old_pid if quadrant == 1, and in that
#     case it has definitely be initialised, eg:
#     
#             if (quadrant == 1) {
#                     old_pid = mfspr(SPRN_PID);
#             ...
#             if (quadrant == 1 && pid != old_pid)
#                     mtspr(SPRN_PID, old_pid);
#     
#     Annotate it to fix the error.
#     
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 f460772291f8171988b2b60141a45706123d0c69
# < make -s -j 48 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86-allmodconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  allmodconfig
# Added to kconfig CONFIG_BUILD_DOCSRC=n
# Added to kconfig CONFIG_MODULE_SIG=n
# Added to kconfig CONFIG_SAMPLES=n
# yes \n | make -s -j 48 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86-allmodconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  oldconfig
yes: standard output: Broken pipe
# make -s -j 48 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86-allmodconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  
You are building kernel with non-retpoline compiler.
Please update your compiler.
make[1]: *** [arch/x86/Makefile:300: checkbin] Error 1
make: *** [Makefile:152: sub-make] Error 2
Command 'make -s -j 48 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86-allmodconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  ' returned non-zero exit status 2
# rm -rf /kisskb/build/powerpc-fixes_x86-allmodconfig_x86_64
# Build took: 0:00:07.921266