fix(darwin): pin main goroutine to OS thread 0 for VZ GUI#5036
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fix(darwin): pin main goroutine to OS thread 0 for VZ GUI#5036trodemaster wants to merge 1 commit into
trodemaster wants to merge 1 commit into
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VZVirtualMachineView requires GUI operations on the process main thread. The existing runtime.LockOSThread() in hostagentAction runs too late — Go's scheduler can migrate the main goroutine to a worker thread before cobra dispatches, causing SIGTRAP on macOS 26 when the VZ driver calls startVirtualMachineWindow. Add an init() that calls runtime.LockOSThread() before main() runs, ensuring the goroutine stays on thread 0 from process start. Fixes: lima-vm#4743
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VZVirtualMachineView requires GUI operations to run on the process main
thread. limactl already calls runtime.LockOSThread() in hostagentAction,
but that runs too late: by the time cobra dispatches the hostagent
subcommand, Go's scheduler has already migrated the main goroutine to a
worker thread. On macOS 26 this causes a SIGTRAP when the VZ driver calls
startVirtualMachineWindow.
Adding runtime.LockOSThread() to an init() function ensures the main
goroutine is pinned to thread 0 before main() runs. The build tag
restricts the file to darwin; Linux and Windows are unaffected.
Tested on macOS 26.5 (25F71), Apple Silicon, with Lima 2.1.2-beta.0:
fresh macOS 26 guest install from IPSW and start of an existing macOS 26
VM with video.display: default both complete without SIGTRAP.
Assisted-by: Commercial LLM tooling
Fixes #4743