# git rev-parse -q --verify 4aa9fc2a435abe95a1e8d7f8c7b3d6356514b37a^{commit}
4aa9fc2a435abe95a1e8d7f8c7b3d6356514b37a
already have revision, skipping fetch
# git checkout -q -f -B kisskb 4aa9fc2a435abe95a1e8d7f8c7b3d6356514b37a
# git clean -qxdf
# < git log -1
# commit 4aa9fc2a435abe95a1e8d7f8c7b3d6356514b37a
# Author: Michal Hocko <mhocko@suse.com>
# Date:   Fri Jan 25 19:08:58 2019 +0100
# 
#     Revert "mm, memory_hotplug: initialize struct pages for the full memory section"
#     
#     This reverts commit 2830bf6f05fb3e05bc4743274b806c821807a684.
#     
#     The underlying assumption that one sparse section belongs into a single
#     numa node doesn't hold really. Robert Shteynfeld has reported a boot
#     failure. The boot log was not captured but his memory layout is as
#     follows:
#     
#       Early memory node ranges
#         node   1: [mem 0x0000000000001000-0x0000000000090fff]
#         node   1: [mem 0x0000000000100000-0x00000000dbdf8fff]
#         node   1: [mem 0x0000000100000000-0x0000001423ffffff]
#         node   0: [mem 0x0000001424000000-0x0000002023ffffff]
#     
#     This means that node0 starts in the middle of a memory section which is
#     also in node1.  memmap_init_zone tries to initialize padding of a
#     section even when it is outside of the given pfn range because there are
#     code paths (e.g.  memory hotplug) which assume that the full worth of
#     memory section is always initialized.
#     
#     In this particular case, though, such a range is already intialized and
#     most likely already managed by the page allocator.  Scribbling over
#     those pages corrupts the internal state and likely blows up when any of
#     those pages gets used.
#     
#     Reported-by: Robert Shteynfeld <robert.shteynfeld@gmail.com>
#     Fixes: 2830bf6f05fb ("mm, memory_hotplug: initialize struct pages for the full memory section")
#     Cc: stable@kernel.org
#     Signed-off-by: Michal Hocko <mhocko@suse.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 4aa9fc2a435abe95a1e8d7f8c7b3d6356514b37a
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_pseries_le_defconfig+NO_NUMA_ppc64le-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  pseries_le_defconfig
# Added to kconfig CONFIG_NUMA=n
# yes \n | make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_pseries_le_defconfig+NO_NUMA_ppc64le-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  oldconfig
yes: standard output: Broken pipe
# make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_pseries_le_defconfig+NO_NUMA_ppc64le-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
WARNING: modpost: Found 3 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
Completed OK
# rm -rf /kisskb/build/linus_pseries_le_defconfig+NO_NUMA_ppc64le-gcc5
# Build took: 0:02:23.501684