Fix connection leak on client abort - #12529
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masaori335 merged 1 commit intoSep 25, 2025
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masaori335
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Sep 24, 2025
| netvc->do_io_shutdown(IO_SHUTDOWN_READWRITE); | ||
| } | ||
| } else if (t_state.txn_conf->cache_http && | ||
| (server_entry != nullptr && server_entry->vc_read_handler == &HttpSM::state_read_server_response_header)) { |
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bneradt
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Sep 24, 2025
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Cherry-picked to 10.1.x branch |
cmcfarlen
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(cherry picked from commit 1754d38)
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…13523) HttpSM::state_watch_for_client_abort reached past the transaction to _ua.get_txn()->get_netvc() to half close the client read side on an early EOS. For HTTP/2 and HTTP/3 that NetVConnection is shared by every stream on the connection, so a single aborted stream stopped the session from reading frames for all of the others. Route the shutdown through the transaction instead: Http2Stream and HQTransaction already implement do_io_shutdown() as a deliberate no-op for exactly this reason, and HTTP/1.x is unaffected because ProxyTransaction forwards to the session's NetVConnection. This is the remaining half of #12529. That change was written to address two regressions from #12502, the second being "HTTP/2 connection is closed if a stream is reset even if other streams are alive", with the stated approach of calling ProxyTransaction::do_io_shutdown() instead of NetVConnection::do_io_shutdown(). It converted the two branches it added but left the pre-existing IO_SHUTDOWN_READ branch calling the NetVConnection directly, so the connection-wide shutdown survived for the case where the tunnel still has a consumer besides the client. A response transform reaches that case readily: the transform stage runs the whole body before anything is written back, so the stream has no write of its own and a client reset arrives as an EOS on the stream's read VIO. Clearing the session's read VIO buffer is not inert, because Http2CommonSession still holds that VIO and re-enables it every 128 frames through HTTP2_SESSION_EVENT_REENABLE. A release build then takes the ntodo() <= 0 path in net_read_io and the connection stalls silently, failing every in-flight stream; a debug build aborts on SSLNetVConnection's `ink_assert(buf.writer())`, the assertion reported in #9448. Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
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…13523) HttpSM::state_watch_for_client_abort reached past the transaction to _ua.get_txn()->get_netvc() to half close the client read side on an early EOS. For HTTP/2 and HTTP/3 that NetVConnection is shared by every stream on the connection, so a single aborted stream stopped the session from reading frames for all of the others. Route the shutdown through the transaction instead: Http2Stream and HQTransaction already implement do_io_shutdown() as a deliberate no-op for exactly this reason, and HTTP/1.x is unaffected because ProxyTransaction forwards to the session's NetVConnection. This is the remaining half of #12529. That change was written to address two regressions from #12502, the second being "HTTP/2 connection is closed if a stream is reset even if other streams are alive", with the stated approach of calling ProxyTransaction::do_io_shutdown() instead of NetVConnection::do_io_shutdown(). It converted the two branches it added but left the pre-existing IO_SHUTDOWN_READ branch calling the NetVConnection directly, so the connection-wide shutdown survived for the case where the tunnel still has a consumer besides the client. A response transform reaches that case readily: the transform stage runs the whole body before anything is written back, so the stream has no write of its own and a client reset arrives as an EOS on the stream's read VIO. Clearing the session's read VIO buffer is not inert, because Http2CommonSession still holds that VIO and re-enables it every 128 frames through HTTP2_SESSION_EVENT_REENABLE. A release build then takes the ntodo() <= 0 path in net_read_io and the connection stalls silently, failing every in-flight stream; a debug build aborts on SSLNetVConnection's `ink_assert(buf.writer())`, the assertion reported in #9448. Co-authored-by: Claude Opus 5 <noreply@anthropic.com> (cherry picked from commit 31eb68f)
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We faced two issues with #12502 deployment.
A). client side connection is not closed when the client aborts during cache read
B). HTTP/2 connection is closed if a stream is reset even if other streams are alive
Approach for A). restore code prior to #12502 and narrow down condition to keep HttpSM running
Approach for B). call
ProxyTransaction::do_io_shutdown()instead ofNetVConnection::do_io_shutdown()Notes from @bryancall:
@bneradt observed client connection leaks in production without this change. The connection count was increasing and the servers were taking out of rotation because we have checks on the connection counts.