# git rev-parse -q --verify c1ed1754f271f6b7acb1bfdc8cfb62220fbed423^{commit}
c1ed1754f271f6b7acb1bfdc8cfb62220fbed423
already have revision, skipping fetch
# git checkout -q -f -B kisskb c1ed1754f271f6b7acb1bfdc8cfb62220fbed423
# git clean -qxdf
# < git log -1
# commit c1ed1754f271f6b7acb1bfdc8cfb62220fbed423
# Author: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
# Date:   Thu Jun 11 17:31:59 2020 +0530
# 
#     powerpc/kvm/book3s64: Fix kernel crash with nested kvm & DEBUG_VIRTUAL
#     
#     With CONFIG_DEBUG_VIRTUAL=y, __pa() checks for addr value and if it's
#     less than PAGE_OFFSET it leads to a BUG().
#     
#       #define __pa(x)
#       ({
#             VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET);
#             (unsigned long)(x) & 0x0fffffffffffffffUL;
#       })
#     
#       kernel BUG at arch/powerpc/kvm/book3s_64_mmu_radix.c:43!
#       cpu 0x70: Vector: 700 (Program Check) at [c0000018a2187360]
#           pc: c000000000161b30: __kvmhv_copy_tofrom_guest_radix+0x130/0x1f0
#           lr: c000000000161d5c: kvmhv_copy_from_guest_radix+0x3c/0x80
#       ...
#       kvmhv_copy_from_guest_radix+0x3c/0x80
#       kvmhv_load_from_eaddr+0x48/0xc0
#       kvmppc_ld+0x98/0x1e0
#       kvmppc_load_last_inst+0x50/0x90
#       kvmppc_hv_emulate_mmio+0x288/0x2b0
#       kvmppc_book3s_radix_page_fault+0xd8/0x2b0
#       kvmppc_book3s_hv_page_fault+0x37c/0x1050
#       kvmppc_vcpu_run_hv+0xbb8/0x1080
#       kvmppc_vcpu_run+0x34/0x50
#       kvm_arch_vcpu_ioctl_run+0x2fc/0x410
#       kvm_vcpu_ioctl+0x2b4/0x8f0
#       ksys_ioctl+0xf4/0x150
#       sys_ioctl+0x28/0x80
#       system_call_exception+0x104/0x1d0
#       system_call_common+0xe8/0x214
#     
#     kvmhv_copy_tofrom_guest_radix() uses a NULL value for to/from to
#     indicate direction of copy.
#     
#     Avoid calling __pa() if the value is NULL to avoid the BUG().
#     
#     Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
#     [mpe: Massage change log a bit to mention CONFIG_DEBUG_VIRTUAL]
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20200611120159.680284-1-aneesh.kumar@linux.ibm.com
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 c1ed1754f271f6b7acb1bfdc8cfb62220fbed423
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_canyonlands_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  44x/canyonlands_defconfig
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_canyonlands_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_canyonlands_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_canyonlands_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  
/kisskb/src/block/genhd.c: In function 'diskstats_show':
/kisskb/src/block/genhd.c:1623:1: warning: the frame size of 1160 bytes is larger than 1024 bytes [-Wframe-larger-than=]
 }
 ^
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_44x_canyonlands_defconfig_powerpc-gcc4.9
# Build took: 0:00:47.111640