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https://issues.apache.org/jira/browse/PROTON-687?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14139399#comment-14139399
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Ken Giusti commented on PROTON-687:
-----------------------------------
>From what I can tell, the engine decrements the delivery's reference count
>when it is removed from the owning links' settled/unsettled delivery list -
>but it never increments the delivery when it is initially put on the list.
>This appears to be causing the corruption, at least for the above test.
I've tried the following fix:
diff --git a/proton-c/src/engine/engine.c b/proton-c/src/engine/engine.c
index 0765a81..b7239d8 100644
--- a/proton-c/src/engine/engine.c
+++ b/proton-c/src/engine/engine.c
@@ -1123,6 +1123,7 @@ pn_delivery_t *pn_delivery(pn_link_t *link,
pn_delivery_tag_t tag)
delivery->updated = false;
delivery->settled = false;
LL_ADD(link, unsettled, delivery);
+ pn_incref(delivery);
delivery->work_next = NULL;
delivery->work_prev = NULL;
delivery->work = false;
This prevents the memory corruption, but it results in memory leaks in
Messenger, and a failure in the delivery event tests:
proton_tests.engine.EventTest.testDeliveryEvents
............................................................................................
fail
Error during test: Traceback (most recent call last):
File "./tests/python/proton-test", line 352, in run
phase()
File
"/home/kgiusti/work/proton/qpid-proton/tests/python/proton_tests/engine.py",
line 2219, in testDeliveryEvents
Event.SESSION_FINAL, Event.CONNECTION_FINAL)
File
"/home/kgiusti/work/proton/qpid-proton/tests/python/proton_tests/engine.py",
line 2087, in expect
return self.expect_oneof(types)
File
"/home/kgiusti/work/proton/qpid-proton/tests/python/proton_tests/engine.py",
line 2102, in expect_oneof
assert False, "actual events %s did not match any of the expected
sequences: %s" % (events, sequences)
AssertionError: actual events [PN_CONNECTION_UNBOUND(<proton.Connection
object at 0xba77ac0>), PN_TRANSPORT(<proton.Transport object at 0xc40d0c0>)]
did not match any of the expected sequences: ((3, 23, 21, 14, 8),)
I'm not sure I understand the intent of the reference counting in the case of
deliveries - I'm turning this bug over to Rafi for his analysis.
> Memory corruption in proton-test
> --------------------------------
>
> Key: PROTON-687
> URL: https://issues.apache.org/jira/browse/PROTON-687
> Project: Qpid Proton
> Issue Type: Bug
> Components: proton-c, python-binding
> Affects Versions: 0.8
> Reporter: Cliff Jansen
> Assignee: Ken Giusti
> Priority: Blocker
> Attachments: segv.patch
>
>
> proton-test will fail with memory violations. Deallocated memory is
> accessed, usually with benign results but less often on Windows.
> The attached crude patch allows the bug to be "discovered" on Linux as well.
> It is not clear to me if the problem is with the swig wrapper, or whether
> this just exposes a reference counting bug in proton-c.
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