Bug 5839

Summary:

I broke XStoreColors on Xlib/XCB

Product:

xorg

Reporter:

Jamey Sharp <jamey>

Component:

Lib/Xlib

Assignee:

Jamey Sharp <jamey>

Status:

RESOLVED FIXED

QA Contact:

Severity:

normal

Priority:

highest

Version:

git

Hardware:

All

OS:

All

Whiteboard:

i915 platform:

i915 features:

Attachments:

Description	Flags
test case that triggers these bugs using XStoreColors.	none

Description Jamey Sharp 2006-02-08 09:53:17 UTC

When converting Xlib/XCB to use only XCB's public API, I assumed that Xlib
protocol stubs don't ever call the Data family of macros more than once per
GetReq. I thought doing so would be a bug because Data can call _XFlush and I
thought that might lead to a race in multi-threaded settings.

It looks like it doesn't lead to a race, though, and XStoreColors (for one) does
call Data many times. This causes an assertion failure in current Xlib/XCB if
XStoreColors is called with more colors than will fit in Xlib's 16kB output
queue. (!)

I need to properly handle multiple calls to Data in Xlib/XCB.

Comment 1 Jamey Sharp 2006-05-08 11:03:51 UTC

I believe I have this fixed in my local GIT repo. I'm waiting for confirmation
that there was ever a bug to begin with before I push the patch, so I can check
that the patch worked.

Comment 2 Jamey Sharp 2006-05-08 16:18:06 UTC

My committed fix repaired the immediate issue but exposed a new one.

The X Test Suite test purpose that illustrates both bugs is in Xlib7,
XCreateColormap purpose 6. The new failure mode is an assert failure in
_XUnlockDisplay.

Comment 3 Eric Anholt 2006-05-10 03:46:21 UTC

XRenderCompositeText8 also calls Data multiple times, and I've hit this using
gconf-editor and clicking apps->evolution->general (boom).  With the latest
bits, I instead hit:

Assertion failed: (XCBGetRequestSent(dpy->xcl->connection) == dpy->request),
function _XUnlockDisplay, file xcl/xcblock.c, line 49.

Comment 4 Jamey Sharp 2006-05-10 04:52:35 UTC

Created attachment 5585 [details]
test case that triggers these bugs using XStoreColors.

storecolors: xcl/xcblock.c:49: _XUnlockDisplay: Assertion
`XCBGetRequestSent(dpy->xcl->connection) == dpy->request' failed.

XCBGetRequestSent(dpy->xcl->connection) is 7; dpy->request is 6.

Comment 5 Jamey Sharp 2006-05-11 10:05:37 UTC

I believe this is finally completely fixed.

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