device: convert runtime.SetFinalizer to AddCleanup#71
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In PR #66, we tried to address a memory leak by avoiding runtime.SetFinalizer for autodrainingInboundQueue and autodrainingOutboundQueue unless there was something to do. However, when there is work to be done, these finalizers still leak memory because they’re still holding on to a cyclical reference to q. This applies to any platform that relies on a bounded device.WaitPool, like Android and iOS which both declare PreallocatedBuffersPerPool. This patch converts this logic to runtime.AddCleanup which is designed to avoid this problem. Updates tailscale/corp#42776 Signed-off-by: Simon Law <sfllaw@tailscale.com>
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lkosewsk
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Jun 18, 2026
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With the caveat that I don't know the code other than in a black box "I am a user" way, it LGTM.
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To testing, I want to say that I took this branch and rebased my original test from #65 that motivated the #66 fix on top. I can verify from the perspective of the original memory leak that this still fixes it, see https://github.com/lkosewsk/wireguard-go/tree/lk/test-sfllaw |
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In PR #66, we tried to address a memory leak by avoiding runtime.SetFinalizer for autodrainingInboundQueue and autodrainingOutboundQueue unless there was something to do.
However, when there is work to be done, these finalizers still leak memory because they’re still holding on to a cyclical reference to q. This applies to any platform that relies on a bounded device.WaitPool, like Android and iOS which both declare PreallocatedBuffersPerPool.
This patch converts this logic to runtime.AddCleanup which is designed to avoid this problem completely.
Updates tailscale/corp#42776