sys/net/gnrc/netif: hold packets after tx_sync split #21855
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Area: network
crasbe
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Type: bug
mguetschow
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Nov 14, 2025
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Thanks a lot for the PR, especially for the provided test! The reasoning for the changes is clear, and I can confirm the test fails on master, but succeeds with the changes.
Just some minor nitpicks about the test code :)
Co-authored-by: mguetschow <[email protected]>
Co-authored-by: mguetschow <[email protected]>
maribu
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Nov 14, 2025
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Looks good, thank you! Please squash :)
maribu
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Nov 14, 2025
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Process: needs backport
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Contribution description
The
gnrc_tx_sync()function currently blocks infinitely after a packet with tx_sync is sent viagnrc_netapi_send()through a legacy netdev when thegnrc_netif_pktqmodule is being used. This happens, because the tc_sync snippet users get increased and the sync snippet can not be released properly.Testing procedure
The test provided only uses nrfmin as legacy netdev. Therefore the test should only work on nrf5x devices. By adjusting the Makefile any other legacy netdev can be used.
The test starts a separate
result_threadand usesztimer_secto schedule a timeout error message after one second. As soon asgnrc_tx_sync()releases, the timeout error message gets canceled and a success message is being sent to theresult_thread.Issues/PRs references
PR #15694; PR #21709