Marcel Meulemans created PROTON-648:
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Summary: 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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