#14983: [app_server] crashes after double clicking Audio Mixer in Cortex
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Reporter: diver | Owner: axeld
Type: bug | Status: new
Priority: critical | Milestone: R1/beta2
Component: Servers/app_server | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking: 15597
Has a Patch: 0 | Platform: All
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Comment (by pulkomandy):
I reproduced the crash 2 or 3 times and I see that it's always in
HWInterface::_AdoptDragBitmap(ServerBitmap const*, BPoint const&).
I see that BListView "resets" fTrack->drag_start on double click. I guess
the idea is that this should cancel the drag operation, but I don't see
how it would achieve that. Quite the opposite, it makes sure the distance
computation in the dragging thread will overflow and give an unexpected
result...
Also, this code will spawn a new mouse tracking thread on every mouse
click, which... well, I think is not the way to go about this. The threads
are snoozing for a while, and if you time the clicks appropriately you can
accumulate as many of them as you want. And then they will all want to
initiate a drag (well, at least they do lock the looper before doing
that).
I think we should rework the code in BListView to not use MouseDownThread,
and just run in the normal message loop instead. This will make this a lot
simpler to trace and debug, if it doesn't solve it.
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Ticket URL: <https://dev.haiku-os.org/ticket/14983#comment:10>
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