The amd64-generic-ubsan builder is consistently failing in BuildImage, with an error that the kernel image won't fit into the partition.  This started on Oct. 18 (previously, the builder was failing in BuildPackages).

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Config:
console= loglevel=7 init=/sbin/init cros_secure oops=panic panic=-1 root=/dev/dm-0 rootwait ro dm_verity.error_behavior=3 dm_verity.max_bios=-1 dm_verity.dev_wait=1 dm="1 vroot none ro 1,0 7602176 verity payload=PARTUUID=%U/PARTNROFF=1 hashtree=PARTUUID=%U/PARTNROFF=1 hashstart=7602176 alg=sha1 root_hexdigest=b9ecb4d9c8842d9f3693ebaf0391767f5097a12c salt=e8f8a2fc17a7bce237a1f88a2e6e5dbb60e76da1e68ba7748155aee49e4cc6fd" noinitrd vt.global_cursor_default=0 kern_guid=%U add_efi_memmap boot=local noresume noswap i915.modeset=1 tpm_tis.force=1 tpm_tis.interrupts=0 nmi_watchdog=panic,lapic 
1+0 records in
1+0 records out
65536 bytes (66 kB, 64 KiB) copied, 0.000197573 s, 332 MB/s
INFO    : Kernel partition image emitted: /mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/hd_vmlinuz.image
INFO    : Root filesystem hash emitted: /mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/rootfs.hash
INFO    : Kernel image A   size is 26217984 bytes.
INFO    : Kernel image B   size is 26217984 bytes.
INFO    : Kernel partition A size is 16777216 bytes.
ERROR   : Fri Oct 19 16:07:49 PDT 2018
ERROR   :  PGID  PPID   PID     ELAPSED     TIME %CPU COMMAND
ERROR   : Arguments of 9924:  '/mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1' 'chromiumos_base_image.bin' '--adjust_part='
ERROR   : Backtrace:  (most recent call is last)
ERROR   :  cros_make_image_bootable:443:main(), called: make_image_bootable '/mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/chromiumos_base_image.bin' 
ERROR   :  cros_make_image_bootable:318:make_image_bootable(), called: check_kernel_size '26217984' '2' 'A' 
ERROR   :  cros_make_image_bootable:177:check_kernel_size(), called: die 'Kernel image won't fit in partition A!' 
ERROR   : 
ERROR   : Error was:
ERROR   :   Kernel image won't fit in partition A!
INFO    : Unmounting image from /mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/stateful_dir and /mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/rootfs_dir
INFO    : Unmounting temporary rootfs /mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/rootfs_dir//build/rootfs.
Cleaning up /usr/local symlinks for /mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/stateful_dir/dev_image
ERROR   : Fri Oct 19 16:07:52 PDT 2018
ERROR   :  PGID  PPID   PID     ELAPSED     TIME %CPU COMMAND
ERROR   : Arguments of 9924:  '/mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1' 'chromiumos_base_image.bin' '--adjust_part='
ERROR   : Backtrace:  (most recent call is last)
ERROR   :  cros_make_image_bootable:443:main(), called: make_image_bootable '/mnt/host/source/src/build/images/amd64-generic/R72-11174.0.2018_10_19_1602-a1/chromiumos_base_image.bin' 
ERROR   :  cros_make_image_bootable:318:make_image_bootable(), called: check_kernel_size '26217984' '2' 'A' 
ERROR   :  cros_make_image_bootable:177:check_kernel_size(), called: die 'Kernel image won't fit in partition A!' 
ERROR   :  common.sh:180:die(), called: die_notrace 'Kernel image won't fit in partition A!' 
ERROR   :  common.sh:1:die_notrace(), called: die 'cros_make_image_bootable failed.' 
ERROR   : 
ERROR   : Error was:
ERROR   :   cros_make_image_bootable failed.
16:07:52: ERROR: 
return code: 1; command: /b/swarming/w/ir/cache/cbuild/repository/chromite/bin/cros_sdk 'PARALLEL_EMERGE_STATUS_FILE=/tmp/tmpOgjYBU' 'FEATURES=separatedebug' 'CHROME_ORIGIN=LOCAL_SOURCE' -- ./build_image '--board=amd64-generic' --replace '--version=' '--builder_path=amd64-generic-ubsan/R72-11174.0.0-b3054460' '--disk_layout=16gb-rootfs' test
cmd=['/b/swarming/w/ir/cache/cbuild/repository/chromite/bin/cros_sdk', 'PARALLEL_EMERGE_STATUS_FILE=/tmp/tmpOgjYBU', 'FEATURES=separatedebug', 'CHROME_ORIGIN=LOCAL_SOURCE', '--', './build_image', u'--board=amd64-generic', '--replace', '--version=', u'--builder_path=amd64-generic-ubsan/R72-11174.0.0-b3054460', u'--disk_layout=16gb-rootfs', u'test'], cwd=/b/swarming/w/ir/cache/cbuild/repository, extra env={'PARALLEL_EMERGE_STATUS_FILE': '/tmp/tmpOgjYBU', 'FEATURES': 'separatedebug', 'CHROME_ORIGIN': 'LOCAL_SOURCE'}

16:07:52: ERROR: ./build_image failed (code=1)
16:07:52: INFO: Translating result ./build_image failed (code=1) to fail.
16:07:52: INFO: Running cidb query on pid 2884, repr(query) starts with <sqlalchemy.sql.expression.Update object at 0x7fc97d9f20d0>
16:07:52: INFO: Running cidb query on pid 2884, repr(query) starts with <sqlalchemy.sql.expression.Insert object at 0x7fc97d9f2610>
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** Finished Stage BuildImage - Fri, 19 Oct 2018 16:07:52 -0700 (PDT)
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16:07:52: INFO: Running cidb query on pid 26863, repr(query) starts with <sqlalchemy.sql.expression.Insert object at 0x7fc97f323f10>