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…adlock Since ros2#966 (jazzy: ros2#973) tf2_ros::Buffer::waitForTransform holds timer_to_request_map_mutex_ while calling BufferCore::addTransformableRequest, which takes transformable_requests_mutex_. BufferCore::testTransformableRequests holds transformable_requests_mutex_ while invoking the ready-callback, which takes timer_to_request_map_mutex_. The two lock orders form an ABBA deadlock; in Nav2 every costmap callback group freezes shortly after start-up. The test forces the interleaving deterministically: a transformable callback (running inside testTransformableRequests) starts a thread that enters waitForTransform and blocks in addTransformableRequest; when the callback returns, the next ready request's callback needs timer_to_request_map_mutex_ and deadlocks. Fails on jazzy HEAD, passes on 0.36.22 and with ros2#979 applied. (cherry picked from commit 54daeda)
Contributor
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If you don't mind, I have included your test in #982. |
Author
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sure, thanks a lot for the quick response! Closing this then |
This was referenced Sep 7, 2026
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Description
The test forces the interleaving deterministically:
This leads to the deadlock with #966, and works fine before, and also works fine with #966 + #979
Relates to #966
Is this user-facing behavior change?
Did you use Generative AI?
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