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https://issues.apache.org/jira/browse/PROTON-648?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14098472#comment-14098472
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Gordon Sim commented on PROTON-648:
-----------------------------------
Absolutely, thanks!
> Memory leaks on aborted connections.
> ------------------------------------
>
> Key: PROTON-648
> URL: https://issues.apache.org/jira/browse/PROTON-648
> Project: Qpid Proton
> Issue Type: Bug
> Components: proton-c
> Affects Versions: 0.7, 0.8
> Reporter: Marcel Meulemans
> Attachments: leak.c
>
>
> When a connection is aborted, open sessions can not be ended and attached
> links can not be not detached properly. Because of this there are some
> references to connection/sessions/links that are not released properly:
> # The session state does not release references to links in the
> {{local_handles/remote_handles}} hash map. This causes a leak because the
> session references links and the links reference the session but the engine
> does have a reference to any of these objects anymore.
> # The transport does not release references to sessions in the
> {{local_channels/remote_channels}} hash map. This is not really a leak
> because the references are released in {{pn_transport_free}}, but i.m.o. they
> should be release when the connection is unbound from the transport, i.e.
> {{pn_unbind_transport()}}.
> The leak can be observed by using the attached test program with ActiveMQ.
> When ActiveMQ is shutdown with CTRL-C it just kills the connection causing a
> transport error (connection aborted) on the client side. When this happens
> the program leaks. See below for the program/valgrind output of the program
> with and without the patch.
> The patch can be found here:
> https://github.com/marcelmeulemans/qpid-proton/commit/e5300da7be015ea874248b6593040d1bd50ac0e3
> - The removed commented code in {{pn_session_finalize}} is the right idea in
> the wrong place; {{pn_session_finalize}} is never called because the
> references that this code releases still exist. The code has been moved to a
> new function {{pn_cleanup_session}} in the transport "class".
> - The {{pn_cleanup_session}} call from {{pn_remove_session}} is needed in the
> case the session is freed ({{pn_session_free}}) manually from application
> code.
> - The {{pn_cleanup_session}} call from {{pn_transport_unbind}} is needed in
> the case the session is automatically freed via the connection.
> - The changes in {{pn_session_close}} solve the real leak describe in *1*
> above.
> *Valgrind output without patch*:
> {noformat}
> ==5607== Memcheck, a memory error detector
> ==5607== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
> ==5607== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
> ==5607== Command: ./leak.symbols
> ==5607==
> Connected to 127.0.0.1:5672
> [0x6671b80]: -> SASL
> [0x6671b80]: <- SASL
> [0x6671b80]:0 <- @sasl-mechanisms(64)
> [sasl-server-mechanisms=@PN_SYMBOL[:ANONYMOUS, :PLAIN]]
> [0x6671b80]:0 -> @sasl-init(65) [mechanism=:ANONYMOUS, initial-response=b""]
> [0x6671b80]:0 <- @sasl-outcome(68) [code=0]
> [0x6671b80]: <- AMQP
> [0x6671b80]: -> AMQP
> [0x6671b80]:0 -> @open(16) [container-id="leak", hostname="leak"]
> [0x6671b80]:0 -> @begin(17) [next-outgoing-id=0, incoming-window=2147483647,
> outgoing-window=0]
> [0x6671b80]:0 -> @attach(18) [name="leak", handle=0, role=true,
> snd-settle-mode=0, rcv-settle-mode=1, source=@source(40)
> [address="queue://leak", durable=0, timeout=0, dynamic=false],
> target=@target(41) [address="queue://leak", durable=0, timeout=0,
> dynamic=false], initial-delivery-count=0]
> [0x6671b80]:0 -> @flow(19) [incoming-window=2147483647, next-outgoing-id=0,
> outgoing-window=0, handle=0, delivery-count=0, link-credit=8, drain=false]
> [0x6671b80]:0 <- @open(16) [container-id="", hostname="",
> max-frame-size=1048576]
> [0x6671b80]:0 <- @begin(17) [remote-channel=0, next-outgoing-id=1,
> incoming-window=0, outgoing-window=0, handle-max=1024]
> [0x6671b80]:0 <- @attach(18) [name="leak", handle=0, role=false,
> snd-settle-mode=2, rcv-settle-mode=0, source=@source(40)
> [address="queue://leak"], target=@target(41) [address="queue://leak"],
> incomplete-unsettled=false, initial-delivery-count=0]
> [0x6671b80]:0 -> @close(24) [error=@error(29)
> [condition=:"amqp:connection:framing-error"]]
> [0x6671b80]:ERROR amqp:connection:framing-error connection aborted
> [0x6671b80]:ERROR[-2] connection aborted
> [0x6671b80]: <- EOS
> [0x6671b80]: -> EOS (-2) connection aborted
> Closed 127.0.0.1:5672
> close: Bad file descriptor
> ==5607==
> ==5607== HEAP SUMMARY:
> ==5607== in use at exit: 14,904 bytes in 306 blocks
> ==5607== total heap usage: 508 allocs, 202 frees, 1,151,697 bytes allocated
> ==5607==
> ==5607== 14,904 (256 direct, 14,648 indirect) bytes in 1 blocks are
> definitely lost in loss record 306 of 306
> ==5607== at 0x4C2935B: malloc (vg_replace_malloc.c:270)
> ==5607== by 0x4150AF: pn_new (object.c:41)
> ==5607== by 0x404D23: pn_connection (engine.c:384)
> ==5607== by 0x40383B: main (leak.c:22)
> ==5607==
> ==5607== LEAK SUMMARY:
> ==5607== definitely lost: 256 bytes in 1 blocks
> ==5607== indirectly lost: 14,648 bytes in 305 blocks
> ==5607== possibly lost: 0 bytes in 0 blocks
> ==5607== still reachable: 0 bytes in 0 blocks
> ==5607== suppressed: 0 bytes in 0 blocks
> ==5607==
> ==5607== For counts of detected and suppressed errors, rerun with: -v
> ==5607== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2)
> {noformat}
> *Valgrind output with patch*:
> {noformat}
> ==4163== Memcheck, a memory error detector
> ==4163== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
> ==4163== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
> ==4163== Command: ./leak.symbols
> ==4163==
> Connected to 127.0.0.1:5672
> [0x6671b80]: -> SASL
> [0x6671b80]:0 -> @sasl-init(65) [mechanism=:ANONYMOUS, initial-response=b""]
> [0x6671b80]: <- SASL
> [0x6671b80]:0 <- @sasl-mechanisms(64)
> [sasl-server-mechanisms=@PN_SYMBOL[:ANONYMOUS, :PLAIN]]
> [0x6671b80]:0 <- @sasl-outcome(68) [code=0]
> [0x6671b80]: <- AMQP
> [0x6671b80]: -> AMQP
> [0x6671b80]:0 -> @open(16) [container-id="leak", hostname="leak"]
> [0x6671b80]:0 -> @begin(17) [next-outgoing-id=0, incoming-window=2147483647,
> outgoing-window=0]
> [0x6671b80]:0 -> @attach(18) [name="leak", handle=0, role=true,
> snd-settle-mode=0, rcv-settle-mode=1, source=@source(40)
> [address="queue://leak", durable=0, timeout=0, dynamic=false],
> target=@target(41) [address="queue://leak", durable=0, timeout=0,
> dynamic=false], initial-delivery-count=0]
> [0x6671b80]:0 -> @flow(19) [incoming-window=2147483647, next-outgoing-id=0,
> outgoing-window=0, handle=0, delivery-count=0, link-credit=8, drain=false]
> [0x6671b80]:0 <- @open(16) [container-id="", hostname="",
> max-frame-size=1048576]
> [0x6671b80]:0 <- @begin(17) [remote-channel=0, next-outgoing-id=1,
> incoming-window=0, outgoing-window=0, handle-max=1024]
> [0x6671b80]:0 <- @attach(18) [name="leak", handle=0, role=false,
> snd-settle-mode=2, rcv-settle-mode=0, source=@source(40)
> [address="queue://leak"], target=@target(41) [address="queue://leak"],
> incomplete-unsettled=false, initial-delivery-count=0]
> [0x6671b80]:0 -> @close(24) [error=@error(29)
> [condition=:"amqp:connection:framing-error"]]
> [0x6671b80]:ERROR amqp:connection:framing-error connection aborted
> [0x6671b80]:ERROR[-2] connection aborted
> [0x6671b80]: <- EOS
> [0x6671b80]: -> EOS (-2) connection aborted
> Closed 127.0.0.1:5672
> close: Bad file descriptor
> ==4163==
> ==4163== HEAP SUMMARY:
> ==4163== in use at exit: 0 bytes in 0 blocks
> ==4163== total heap usage: 508 allocs, 508 frees, 1,151,697 bytes allocated
> ==4163==
> ==4163== All heap blocks were freed -- no leaks are possible
> ==4163==
> ==4163== For counts of detected and suppressed errors, rerun with: -v
> ==4163== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
> {noformat}
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