twm in desktop mode crashes the server

[totaam]

Issue migrated from trac ticket # 1565

component: server | priority: minor | resolution: wontfix | keywords: x11

2017-07-04 06:22:35: antoine created the issue

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trying to move a window or using the twm menu results in a complete deadlock.

killing xpra does not help, the X11 server is hosed and no longer responds.

Looks like an upstream bug.

[totaam]

2017-07-04 06:24:07: antoine changed status from new to assigned

[totaam]

2017-07-04 06:24:07: antoine edited the issue description

[totaam]

2017-07-04 06:35:59: antoine changed priority from critical to minor

[totaam]

2017-07-04 06:35:59: antoine commented

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Not an xpra bug - lowering priority, this can be reproduced with just dummy + twm:

/usr/libexec/Xorg -noreset -novtswitch -nolisten tcp -config /etc/xpra/xorg.conf :10
#verify we can access the display:
DISPLAY=:10 xprop -root
DISPLAY=:10 xterm&
DISPLAY=:10 twm&
#now click on the title bar of the xterm:
DISPLAY=:10 xdotool mousemove 90 10 mousedown 1
#and now the X11 server is inaccessible:
DISPLAY=:10 xprop -root

[totaam]

2017-07-04 06:53:30: antoine commented

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Reported upstream: twm deadlocks the server

[totaam]

2017-07-16 13:15:32: antoine changed status from assigned to closed

[totaam]

2017-07-16 13:15:32: antoine set resolution to wontfix

[totaam]

2017-07-16 13:15:32: antoine commented

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As I was kindly reminded: in this response, this is not a bug - twm grabs the server, and nothing ever gets a chance to emit the click release event that would cause twm to release the grab.

The only solution that I can think of at this point is to use virtual input devices (uinput, etc - #173) instead of xtest.