device: fix some lock ordering violations, add a test for a deadlock we hit#55
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device: fix some lock ordering violations, add a test for a deadlock we hit#55
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…we hit Discovered by a tool + test that will come in a future change. Updates tailscale/tailscale#19513 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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| // because SendKeepalive can reach CreateMessageInitiation which acquires | ||
| // staticIdentity.RLock; holding peers.RLock across that path would | ||
| // invert the staticIdentity < peers hierarchy (see lock-ordering.md). | ||
| device.peers.RLock() |
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note for posterity: i have an upstream patch been waiting in review since 2023 that removes the rwlock from the path because it's actually slower than a mutex when measured in the real world, and it's over-complicated.
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yeah, we should make this a regular mutex probably
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Discovered by a tool + test that will come in a future change.
Updates tailscale/tailscale#19513