Fix fence completion race in virtio-gpu worker#608
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slp merged 1 commit intocontainers:mainfrom Mar 27, 2026
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When fences complete out of order (e.g., an immediate-retire for fence N+1 arrives before the timeline signal for fence N), the unconditional insert() would overwrite the higher fence_id with the lower one. This causes fence N+1 to appear incomplete forever, hanging the guest. Use entry().or_insert() with a max check so only strictly higher fence_ids update the completed_fences map. Signed-off-by: Adam Ford <adam.ford@anodize.com>
aford173
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MatiasVara,
dorindabassey,
jakecorrenti,
mtjhrc,
slp and
tylerfanelli
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When fences complete out of order (e.g., an immediate-retire for fence N+1 arrives before the timeline signal for fence N), the unconditional insert() would overwrite the higher fence_id with the lower one. This causes fence N+1 to appear incomplete forever, hanging the guest.
Use entry().or_insert() with a max check so only strictly higher fence_ids update the completed_fences map.
Note to maintainers: The previous submission was targeting 1.17.x branch, this is effectively the same patch with requested fixes targeting main instead if the 1.17x. branch. Please forgive the noise if this is not the proper way to submit.