amd64-generic-goofy-release SignerTest stage has been failing for the past 2 months at least:
https://uberchromegw.corp.google.com/i/chromeos/builders/amd64-generic-goofy-release?numbuilds=200

For example:
https://uberchromegw.corp.google.com/i/chromeos/builders/amd64-generic-goofy-release/builds/863/steps/SignerTest/logs/stdio

15:17:03: INFO: RunCommand: /b/cbuild/internal_master/chromite/bin/cros_sdk 'PARALLEL_EMERGE_STATUS_FILE=/tmp/tmpxrPcfq' -- ./security_test_image '--board=amd64-generic-goofy' in /b/cbuild/internal_master
/b/cbuild/internal_master/chromite/third_party/google/protobuf/__init__.py:37: UserWarning: Module simplejson was already imported from /b/build/third_party/simplejson/__init__.pyc, but /usr/local/lib/python2.7/dist-packages is being added to sys.path
  __import__('pkg_resources').declare_namespace(__name__)
INFO    security_test_image: Loading baselines from /mnt/host/source/cros-signing/security_test_baselines
INFO    security_test_image: Using /mnt/host/source/src/build/images/amd64-generic-goofy/R57-9008.0.0/recovery_image.bin
INFO    security_test_image: Using vboot_reference.git rev 42b74d2677786cf9e135873b574428bdd74bd3fb
INFO    security_test_image: Running ensure_no_nonrelease_files.sh
INFO    security_test_image: Running ensure_sane_lsb-release.sh
Loading config from /mnt/host/source/cros-signing/security_test_baselines/ensure_sane_lsb-release.config... Done.
INFO    security_test_image: Running ensure_secure_kernelparams.sh
Kernel dm= parameter does not match any expected values!
Actual:   1 vroot none ro 1,0 4096000 verity payload=PARTUUID=%U/PARTNROFF=1 hashtree=PARTUUID=%U/PARTNROFF=1 hashstart=4096000 alg=sha1 root_hexdigest=7261e7fd5bad3c124dc06bd2c3357b20be1de611 salt=1a4cec18be8e9da952b2389f2376c78465825faf70eec3f7deb6a200bd303e82
Expected: 
Expected (regex): 
Unexpected kernel parameters found:
 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 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 
Debug output:
required_kparams=(
	''
)
required_kparams_regex=(
	''
)
optional_kparams=(
	''
)
optional_kparams_regex=(
	''
)
required_dmparams=(
	''
)
required_dmparams_regex=(
	''
)

kparams='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 4096000 verity payload=PARTUUID=%U/PARTNROFF=1 hashtree=PARTUUID=%U/PARTNROFF=1 hashstart=4096000 alg=sha1 root_hexdigest=7261e7fd5bad3c124dc06bd2c3357b20be1de611 salt=1a4cec18be8e9da952b2389f2376c78465825faf70eec3f7deb6a200bd303e82" 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 '

dmparams='1 vroot none ro 1,0 4096000 verity payload=PARTUUID=%U/PARTNROFF=1 hashtree=PARTUUID=%U/PARTNROFF=1 hashstart=4096000 alg=sha1 root_hexdigest=7261e7fd5bad3c124dc06bd2c3357b20be1de611 salt=1a4cec18be8e9da952b2389f2376c78465825faf70eec3f7deb6a200bd303e82'

kparams_nodm='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  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 '

mangled_dmparams='1 vroot none ro 1,0 4096000 verity payload=PARTUUID=%U/PARTNROFF=1 hashtree=PARTUUID=%U/PARTNROFF=1 hashstart=4096000 alg=sha1 root_hexdigest=MAGIC_HASH salt=MAGIC_SALT'

(actual error will be at the top of output)
ERROR   security_test_image: secure_kernelparams: test failed
INFO    security_test_image: Running ensure_not_ASAN.sh
ERROR   security_test_image: 1 tests failed
15:17:19: ERROR: 
return code: 1; command: /b/cbuild/internal_master/chromite/bin/cros_sdk 'PARALLEL_EMERGE_STATUS_FILE=/tmp/tmpxrPcfq' -- ./security_test_image '--board=amd64-generic-goofy'
cwd=/b/cbuild/internal_master, extra env={'PARALLEL_EMERGE_STATUS_FILE': '/tmp/tmpxrPcfq'}

This appears to be somewhat related to  Issue 605595 , but the failure message looks different.