#59 locked sessions, multiple /usr/sbin/xrdp children

[Nestor Urquiza]

Hello,

Randomly users won't be able to connect to xrdp obtaining just a blank (black/blue) screen after login.

Looking into the running processes:

$ ps -ef|grep xrdp
root 1208 1 0 Nov03 ? 00:00:00 /usr/sbin/xrdp
root 1211 1 0 Nov03 ? 00:00:00 /usr/sbin/xrdp-sesman
dev 1760 1211 0 Nov03 ? 00:00:00 /usr/sbin/xrdp-sessvc 1762 1761
root 1761 1760 0 Nov03 ? 00:00:00 /usr/sbin/xrdp-sesman
dev 1765 1760 0 Nov03 ? 00:00:01 xrdp-chansrv
root 3244 1208 1 Nov08 ? 00:07:44 /usr/sbin/xrdp
root 3775 1208 0 07:35 ? 00:00:00 /usr/sbin/xrdp
root 3780 1208 0 07:38 ? 00:00:00 /usr/sbin/xrdp
root 4638 1208 0 08:00 ? 00:00:00 /usr/sbin/xrdp
root 4643 1208 0 08:05 ? 00:00:00 /usr/sbin/xrdp
root 5449 1208 0 08:38 ? 00:00:00 /usr/sbin/xrdp

Note how many instance of xrdp are spawned. If we kill all children of 1208 (oldest xrdp process) we can login again without issues. We tried to replicate login several times but we could not get more than one child. So definitely it looks like an xrdp bug.

$ sudo kill -9 3244 3775 3780 4638 4643 5449

What is the command t show the xrdp version BTW? Using strings we get the below so hopefully this will provide enough information to receive some help:

dev@udesktop9:~$ strings /usr/sbin/xrdp|grep "xrdp.*[0-9].[0-9]"
xrdp_%8.8x_main_term
xrdp_%8.8x_main_sync
xrdp:xrdp_cache [%10.10u]:
xrdp_%8.8x_listen_pro_done_event
xrdp:xrdp_mm [%10.10u]:
xrdp_mm_process_rail_create_window: 0x%8.8x
xrdp_mm_process_rail_destroy_window 0x%8.8x
xrdp_mm_process_rail_show_window 0x%8.8x %x
xrdp_%8.8x_process_self_term_event_%8.8x
xrdp_%8.8x_wm_login_mode_event_%8.8x
xrdp:xrdp_encoder [%10.10u]:
xrdp_%8.8x_encoder_term
xrdp_%8.8x_encoder_event_to_proc
xrdp_%8.8x_encoder_event_processed

Probably I should have started saying that I am using https://github.com/scarygliders/X11RDP-o-Matic.git to install xrdp in Ubuntu 14.04 with LXDE. We created a wrapper around it as described in http://thinkinginsoftware.blogspot.com/2012/11/vdi-path-access-linux-desktop-remotely.html

Thanks!

• Nestor