Deadock Xorg runing strace on a client (from within a client terminal)

Peter Harris peter.harris at
Thu Aug 28 11:30:55 PDT 2008

Adam Jackson wrote:
> On Thu, 2008-08-28 at 15:50 +0100, Alan Cox wrote:
<about strace>
>> If you trace through a server grab you may well end up with the app you
>> are tracing owning a grab on the server and preventing the other clients
>> writing. Its an annoying bit of historic X design.
> That's only a deadlock if the client with the grab is waiting for the
> tracing client to do something before releasing the grab.  This is
> almost certainly not the case here.

Client grabs server.
xterm blocks writing to server.
strace blocks writing to xterm.
Client blocks in strace.

This can easily deadlock if there is enough strace activity under the
grab to fill up the various pipe/socket buffers.

Peter Harris
     Hummingbird Connectivity - A Division of Open Text
Peter Harris          
Research and Development        Phone: +1 905 762 6001
peter.harris at    Toll Free: 1 877 359 4866

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