010dd5c6f2
Discovered by a tool + test that will come in a future change. Updates tailscale/tailscale#19513 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
27 lines
879 B
Markdown
27 lines
879 B
Markdown
# Lock Ordering in wireguard-go/device
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## Lock hierarchy
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Locks must be acquired in the order listed below. A goroutine holding a
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lock with a higher number must never attempt to acquire a lock with a
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lower number.
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```
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Level 0 device.state.Mutex
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Level 1 device.ipcMutex (sync.RWMutex)
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Level 2 device.net.RWMutex
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Level 3 device.staticIdentity.RWMutex
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Level 4 device.peers.RWMutex
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Level 5 peer.state.Mutex
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Level 6 peer.handshake.mutex (sync.RWMutex)
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Level 7 peer.keypairs.RWMutex
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Level 8 device.allowedips.mu (sync.RWMutex)
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Level 9 device.indexTable.RWMutex
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Level 10 peer.endpoint.Mutex
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Level 11 device.cookieChecker.RWMutex
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Level 12 peer.cookieGenerator.RWMutex
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Level 13 Timer.modifyingLock / Timer.runningLock
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```
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Not every pair of locks appears in practice; the ordering above is the
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transitive closure of the pairs that do.
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