Dext signing issue on Sequoia Beta

I am developing a PCIDriverKit dext, and testing on Sequoia Beta (Version 15.0 Beta, 24A5298h). Both the dext and the "owning" application build on Xcode 16.0 beta 4. I can run the owning application and register the dext.
When the OS attempts to load the dext, though, code signing validation errors occur:

2024-07-30 15:54:02.386 Df kernel[0:ae6a] Driver com.company.Dext-Loader.dext has crashed 0 time(s)
2024-07-30 15:54:02.386 Df kernel[0:ae6a] DK: Dext_Loader_Driver-0x100001464 waiting for server com.company.Dext-Loader.dext-100001464
2024-07-30 15:54:02.388 Df kernelmanagerd[112:abb5] Found 1 dexts with bundle identifier com.company.Dext-Loader.dext
2024-07-30 15:54:02.388 Df kernelmanagerd[112:abb5] Using unique id a0cf49ca3ea45f5d54a3e8644e2dde6b0e8666c649c1e9513ca4166919038b53 to pick dext matching bundle identifier com.company.Dext-Loader.dext
2024-07-30 15:54:02.388 Df kernelmanagerd[112:abb5] Picked matching dext for bundle identifier com.company.Dext-Loader.dext: Dext com.company.Dext-Loader.dext v34 in executable dext bundle com.company.Dext-Loader.dext at /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext
2024-07-30 15:54:02.389 I  kernel[0:ae71] igmp_domifreattach: reattached igmp_ifinfo for ifp XHC
2024-07-30 15:54:02.389 I  kernel[0:ae71] mld_domifreattach: reattached mld_ifinfo for ifp XHC2
2024-07-30 15:54:02.389 Df kernelmanagerd[112:abb5] DextRecordTable read from plist: {

com.company.Dext-Loader.dext: 
	MRS-> Optional(( path: /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext; state: loaded )) 
history-> [
	( path: /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext; state: loaded )
]
}
2024-07-30 15:54:02.389 Df kernelmanagerd[112:abb5] Launching dext com.company.Dext-Loader.dext com.company.Dext-Loader.dext 0x100001464 a0cf49ca3ea45f5d54a3e8644e2dde6b0e8666c649c1e9513ca4166919038b53
2024-07-30 15:54:02.390 I  kernelmanagerd[112:abb5] [com.apple.km:DextLaunch] Skipping addBreadcrumbForDextWithIdentifier for <private> 0
2024-07-30 15:54:02.389 Df kernel[0:ae71] ifnet_attach: Waiting for all kernel threads created for interface XHC2 to get scheduled at least once.
2024-07-30 15:54:02.389 Df kernel[0:ae71] ifnet_attach: All kernel threads created for interface XHC2 have been scheduled at least once. Proceeding.
2024-07-30 15:54:02.390 Df kernelmanagerd[112:abb5] Launching driver extension: Dext com.company.Dext-Loader.dext v34 in executable dext bundle com.company.Dext-Loader.dext at /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext
2024-07-30 15:54:02.479 E  kernel[0:a9fb] (Sandbox) 1 duplicate report for Sandbox: imagent(633) deny(1) mach-lookup com.apple.contactsd.persistence
2024-07-30 15:54:02.479 E  kernel[0:a9fb] (Sandbox) Sandbox: taskgated-helper(2985) deny(1) user-preference-read kCFPreferencesAnyApplication
2024-07-30 15:54:02.483 Df kernel[0:ae73] (AppleMobileFileIntegrity) AMFI: code signature validation failed.
2024-07-30 15:54:02.483 Df kernel[0:ae73] (AppleMobileFileIntegrity) AMFI: bailing out because of restricted entitlements.
2024-07-30 15:54:02.483 Df kernel[0:ae73] (AppleMobileFileIntegrity) AMFI: When validating /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext/com.company.Dext-Loader.dext:
  Code has restricted entitlements, but the validation of its code signature failed.
Unsatisfied Entitlements:
2024-07-30 15:54:02.483 Df kernel[0:ae73] mac_vnode_check_signature: /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext/com.company.Dext-Loader.dext: code signature validation failed fatally: When validating /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext/com.company.Dext-Loader.dext:
  Code has restricted entitlements, but the validation of its code signature failed.
Unsatisfied Entitlements:
2024-07-30 15:54:02.483 Df kernel[0:ae73] validation of code signature failed through MACF policy: 1
2024-07-30 15:54:02.483 Df kernel[0:ae73] check_signature[pid: 2984]: error = 1
2024-07-30 15:54:02.483 Df kernel[0:ae73] proc 2984: load code signature error 4 for file "com.company.Dext-Loader.dext"
2024-07-30 15:54:02.485 Df kernelmanagerd[112:abb5] [com.apple.libxpc.OSLaunchdJob:all] <OSLaunchdJob | handle=46B92B57-A90A-4EBD-8EF4-54313C6EE332>: submitAndStart completed, info=spawn failed, error=162: Codesigning issue
2024-07-30 15:54:02.483 Df kernel[0:ae73] (Sandbox) /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext/com.company.Dext-Loader.dext[2984] ==> com.apple.dext
2024-07-30 15:54:02.485 E  kernelmanagerd[112:abb5] [com.apple.libxpc.OSLaunchdJob:all] <OSLaunchdJob | handle=46B92B57-A90A-4EBD-8EF4-54313C6EE332>: job failed to spawn, plist={
	ProcessType => Driver
	_ManagedBy => com.apple.kernelmanagerd
	CFBundleIdentifier => com.company.Dext-Loader.dext
	_JetsamPropertiesIdentifier => com.company.Dext-Loader.dext
	LimitLoadToSessionType => System
	_DextCheckInPort => <mach send right: 0xbd486ccc0> { name = 15679, right = send, urefs = 2 }
	UserName => _driverkit
	_NullBootstrapPort => true
	ReslideSharedCache => false
	LaunchOnlyOnce => true
	Label => com.company.Dext-Loader.dext-0x100001464
	RunAtLoad => true
	ProgramArguments => [<capacity = 8>
		0: /Library/SystemExtensions/B1BF8CDC-CB24-4F25-A8CA-D7A60D814861/com.company.Dext-Loader.dext.dext/com.company.Dext-Loader.dext
		1: com.company.Dext-Loader.dext
		2: 0x100001464
		3: com.company.Dext-Loader.dext
	]
	SandboxProfile => com.apple.dext
}

The Xcode project uses these signing options:

  • Automatically manage signing
  • Team: Company
  • Provisioning Profile: Xcode Managed Profile
  • Signing Certificate: Apple Development: <my name> (<my developer code>)

The same project, with the same signing options, builds and loads its dext without issues from Xcode 15.3 on Sonoma 14.5. That same dext binary from Xcode 15.3 loads and passes the signature checks on Sequoia, but using Xcode on Sequoia is when the signature validation fails.

Can anyone suggest a way to resolve these signature validation errors? (Other than just developing on Sonoma and testing on Sequoia?)

Dext signing issue on Sequoia Beta
 
 
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