Bug 30343 - XCB leaks memory and socket file descriptor on connection failure.
Summary: XCB leaks memory and socket file descriptor on connection failure.
Alias: None
Product: XCB
Classification: Unclassified
Component: Library (show other bugs)
Version: unspecified
Hardware: All All
: medium normal
Assignee: Josh Triplett
QA Contact: xcb mailing list dummy
Keywords: patch
Depends on:
Reported: 2010-09-23 05:04 UTC by jp.sittingduck
Modified: 2010-09-23 15:09 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

A test-case to show leak. (878 bytes, text/x-csrc)
2010-09-23 05:04 UTC, jp.sittingduck
Here is my proposed patch. (1.47 KB, patch)
2010-09-23 05:06 UTC, jp.sittingduck
Details | Splinter Review
Patch to allow disconnecting connections in the error state (1.75 KB, patch)
2010-09-23 14:19 UTC, Josh Triplett
Details | Splinter Review

Description jp.sittingduck 2010-09-23 05:04:14 UTC
Created attachment 38899 [details]
A test-case to show leak.

When there is a connection error, XCB sets has_error to 1 in xcb_connection_t, which precludes clean-up (since, if has_error is set to 1, the connection may be a pointer to the error_connection variable). Attached is a test-case that simulates a connection failure. Running it in valgrind will show not only a memory leak, but a file descriptor leak (the socket) too.
Comment 1 jp.sittingduck 2010-09-23 05:06:53 UTC
Created attachment 38900 [details] [review]
Here is my proposed patch.

This is my proposed patch that adds an is_open field to xcb_connection_t, which is checked in xcb_disconnect so that an open connection can be cleaned up despite having had an error.

error_connection in xcb_conn.c is changed from an int to an xcb_connection_t, with has_error and is_open set to 1 and 0 respectively.
Comment 2 Jamey Sharp 2010-09-23 12:04:06 UTC
In an amusing coincidence, Josh has a different patch sitting in his queue that we wrote last week for this same issue. Josh?
Comment 3 Josh Triplett 2010-09-23 14:19:54 UTC
Created attachment 38920 [details] [review]
Patch to allow disconnecting connections in the error state

Jamey and I wrote the attached patch on the plane back from XDS 2010:

Subject: [PATCH] Allow disconnecting connections that are in error state.

In support of this, consolidate the two static error_connection
definitions into one so we don't try to free the static out-of-memory

Commit by Josh Triplett and Jamey Sharp.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Jamey Sharp <jamey@minilop.net>
Comment 4 Josh Triplett 2010-09-23 15:09:47 UTC
I confirmed that the test case no longer leaks the connection when used with this patch, so I've pushed the patch to libxcb master.  Closing this bug.

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