device, cmd/check-lockorder: add static analysis tool for lock ordering#56
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device, cmd/check-lockorder: add static analysis tool for lock ordering#56
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This adds cmd/check-lockorder, a static analyzer that builds a lock-after directed graph from the device package and reports cycles (potential deadlocks) and reentrant RLocks (which deadlock with a pending writer), and hook it up to CI to fail so we don't regress. This also does some no-op (I believe) refactoring of some device code to make locking easier for both humans and cmd/check-lockorder to follow, without having to hard-code exceptions in cmd/check-lockorder or make it more complicated. This is the tool that previously found the deadlock fixed by 770e3f5. Updates tailscale/tailscale#19513 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
raggi
reviewed
Apr 27, 2026
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| func (device *Device) GetOutboundElementsContainer() *QueueOutboundElementsContainer { | ||
| c := device.pool.outboundElementsContainer.Get().(*QueueOutboundElementsContainer) | ||
| c.Mutex = sync.Mutex{} |
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i had forgotten this was here, this is super dangerous
raggi
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Apr 27, 2026
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I focused my review on the wireguard side stuff. cmd/check-lockorder looks plausible, but it's a good chunk of code without tests, we might want to add tests if we're gunna use it long term.
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This adds cmd/check-lockorder, a static analyzer that builds a
lock-after directed graph from the device package and reports cycles
(potential deadlocks) and reentrant RLocks (which deadlock with a
pending writer), and hook it up to CI to fail so we don't regress.
This also does some no-op (I believe) refactoring of some device code
to make locking easier for both humans and cmd/check-lockorder to follow,
without having to hard-code exceptions in cmd/check-lockorder or make
it more complicated.
This is the tool that previously found the deadlock fixed by 770e3f5.
Updates tailscale/tailscale#19513