Fix infinite loop in VOLATILE DataReader init_shared_segment#6343
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PavelGuzenfeld wants to merge 1 commit intoeProsima:masterfrom
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Fix infinite loop in VOLATILE DataReader init_shared_segment#6343PavelGuzenfeld wants to merge 1 commit intoeProsima:masterfrom
PavelGuzenfeld wants to merge 1 commit intoeProsima:masterfrom
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When a late-joining VOLATILE DataReader initializes against a running DataWriter using data-sharing, init_shared_segment() could spin forever in the fast-forward loop. The loop condition used || (OR) which kept iterating even when get_next_unread_payload returned unknown — as long as next_payload_ had not caught up with a concurrently advancing writer. Fix: change the condition from || to && (AND). The loop should only continue advancing when there IS a valid unread payload AND we haven't reached the current end position. When no more payloads are available (unknown sequence number), the reader is caught up and should stop. Fixes eProsima#6338 Signed-off-by: Pavel Guzenfeld <me@pavelguzenfeld.com>
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Summary
Fixes #6338
When a late-joining VOLATILE DataReader initializes against a running DataWriter using data-sharing,
init_shared_segment()could spin forever. The fast-forward loop condition used||(OR):while (ch.sequenceNumber != SequenceNumber_t::unknown() || next_payload_ != current_end)This kept iterating even when
get_next_unread_payloadreturned unknown — as long asnext_payload_hadn't caught up with a concurrently advancing writer. One CPU core goes to 100%, and discovery threads block behind the PDP mutex.Fix: change
||to&&. The loop should only continue when there IS a valid unread payload AND we haven't reached the end.Test plan
Signed-off-by: Pavel Guzenfeld me@pavelguzenfeld.com