dbus_connection_send_with_reply_and_block eats 100% CPU then eventually times out

[Alex Brooks]

Hi,

I've been fighting for a long time with what now looks like a libdbus bug.
I have a cut-down test program which calls a dbus method of 
wpa_supplicant at 100Hz, it does this happily for several hours then at 
some point the behaviour changes: any future calls sit at 100% CPU for 
25sec then time out.
I don't think the problem is on the wpa_supplicant side: other clients 
can simultaneously make this call without any problems, and restarting 
the client fixes it.
[I'm running at 100Hz because the faster I run this loop, the faster it 
reproduces the problem.  CPU load sits below 20% before I hit the bug].

I posted details and a sample program as a Qt bug report (I'm using the 
QDBus wrapper and thought it might be a Qt bug initially):
https://bugreports.qt.io/browse/QTBUG-43550

Does anyone have any thoughts?


Thanks,

Alex