# git rev-parse -q --verify 3dc709e518b47386e6af937eaec37bb36539edfd^{commit}
3dc709e518b47386e6af937eaec37bb36539edfd
already have revision, skipping fetch
# git checkout -q -f -B kisskb 3dc709e518b47386e6af937eaec37bb36539edfd
# git clean -qxdf
# < git log -1
# commit 3dc709e518b47386e6af937eaec37bb36539edfd
# Author: Xiaoming Ni <nixiaoming@huawei.com>
# Date:   Fri Nov 26 12:11:53 2021 +0800
# 
#     powerpc/85xx: Fix oops when CONFIG_FSL_PMC=n
#     
#     When CONFIG_FSL_PMC is set to n, no value is assigned to cpu_up_prepare
#     in the mpc85xx_pm_ops structure. As a result, oops is triggered in
#     smp_85xx_start_cpu().
#     
#       smp: Bringing up secondary CPUs ...
#       kernel tried to execute user page (0) - exploit attempt? (uid: 0)
#       BUG: Unable to handle kernel instruction fetch (NULL pointer?)
#       Faulting instruction address: 0x00000000
#       Oops: Kernel access of bad area, sig: 11 [#1]
#       ...
#       NIP [00000000] 0x0
#       LR [c0021d2c] smp_85xx_kick_cpu+0xe8/0x568
#       Call Trace:
#       [c1051da8] [c0021cb8] smp_85xx_kick_cpu+0x74/0x568 (unreliable)
#       [c1051de8] [c0011460] __cpu_up+0xc0/0x228
#       [c1051e18] [c0031bbc] bringup_cpu+0x30/0x224
#       [c1051e48] [c0031f3c] cpu_up.constprop.0+0x180/0x33c
#       [c1051e88] [c00322e8] bringup_nonboot_cpus+0x88/0xc8
#       [c1051eb8] [c07e67bc] smp_init+0x30/0x78
#       [c1051ed8] [c07d9e28] kernel_init_freeable+0x118/0x2a8
#       [c1051f18] [c00032d8] kernel_init+0x14/0x124
#       [c1051f38] [c0010278] ret_from_kernel_thread+0x14/0x1c
#     
#     Fixes: c45361abb918 ("powerpc/85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n")
#     Reported-by: Martin Kennedy <hurricos@gmail.com>
#     Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
#     Tested-by: Martin Kennedy <hurricos@gmail.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20211126041153.16926-1-nixiaoming@huawei.com
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/s390-linux/bin/s390-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/s390-linux/bin/s390-linux-ld --version
# < git log --format=%s --max-count=1 3dc709e518b47386e6af937eaec37bb36539edfd
# < make -s -j 32 ARCH=s390 O=/kisskb/build/powerpc-fixes_s390-defconfig_s390x-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/s390-linux/bin/s390-linux-  defconfig
# < make -s -j 32 ARCH=s390 O=/kisskb/build/powerpc-fixes_s390-defconfig_s390x-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/s390-linux/bin/s390-linux-  help
# make -s -j 32 ARCH=s390 O=/kisskb/build/powerpc-fixes_s390-defconfig_s390x-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/s390-linux/bin/s390-linux-  olddefconfig
# make -s -j 32 ARCH=s390 O=/kisskb/build/powerpc-fixes_s390-defconfig_s390x-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/s390-linux/bin/s390-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_s390-defconfig_s390x-gcc11
# Build took: 0:03:14.726705