boinc_client gets blocked on XOpenDisplay () when 2 Xorg sessions are open #2199
Description
When two graphic sessions are opened on my system with only one active, boinc_client gets eventually stuck forever waiting on XOpenDisplay(). Killing the non-active Xorg session or switching back to it will unstuck boinc_client.
% ps aux|grep boinc
boinc 616 0.1 0.1 76512 16276 ? SNsl oct.25 11:27 /usr/bin/boinc_client --dir /var/lib/boinc --redirectio
boinc 6469 27.0 2.7 375236 227700 ? SNl oct.28 471:12 ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3.78_x86_64-pc-linux-gnu @G187193_1-50_MAP_hyb_TMP_v02_i01_t000__krypton.flags -in:file:boinc_wu_zip G187193_1-50_MAP_hyb_TMP_v02_i01_t000__krypton.zip -run:protocol jd2_scripting -silent_gz -mute all -out:file:silent default.out -nstruct 10000 -cpu_run_time 28800 -boinc:max_nstruct 600 -checkpoint_interval 120 -database minirosetta_database -in::file::zip minirosetta_database.zip -boinc::watchdog -run::rng mt19937 -constant_seed -jran 1240652
boinc 8431 15.0 0.0 0 0 ? ZN oct.28 238:57 [minirosetta_3.7] <defunct>
boinc 9481 18.7 0.0 0 0 ? ZN oct.28 267:20 [wcgrid_mcm1_7.3] <defunct>
boinc 9770 7.4 0.0 0 0 ? ZN oct.28 102:17 [minirosetta_3.7] <defunct>
boinc 9822 18.9 0.0 0 0 ? ZN oct.28 257:39 [wcgrid_mcm1_7.3] <defunct>
boinc 14127 0.0 0.0 0 0 ? ZN oct.28 0:06 [primegrid_genef] <defunct>
boinc 14128 17.8 0.0 0 0 ? ZN oct.28 226:39 [wcgrid_mcm1_7.3] <defunct>
paul 21201 0.2 1.4 2969360 120644 ? Sl 19:10 0:00 /usr/bin/boincmgr
paul 21295 0.0 0.0 11204 896 pts/1 S+ 19:12 0:00 grep --color=auto boinc
Backtrace (incomplete) but we can see boinc_client is stuck waiting on XOpenDisplay () to return.
Attaching to process 616
[New LWP 827]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00007f50e53a7a3d in poll () from /lib64/libc.so.6
(gdb) bt
#0 0x00007f50e53a7a3d in poll () from /lib64/libc.so.6
#1 0x00007f50e50aea9b in ?? () from /usr/lib64/libxcb.so.1
#2 0x00007f50e50ac693 in xcb_connect_to_fd () from /usr/lib64/libxcb.so.1
#3 0x00007f50e50b03d9 in xcb_connect_to_display_with_auth_info () from /usr/lib64/libxcb.so.1
#4 0x00007f50e63d674a in _XConnectXCB () from /usr/lib64/libX11.so.6
#5 0x00007f50e63c7702 in XOpenDisplay () from /usr/lib64/libX11.so.6
#6 0x0000000000494494 in ?? ()
#7 0x00000000004948cf in ?? ()
#8 0x000000000042090e in ?? ()
#9 0x00000000004732c0 in ?? ()
#10 0x00000000004084a0 in ?? ()
#11 0x00007f50e52e9640 in __libc_start_main () from /lib64/libc.so.6
#12 0x0000000000408a59 in ?? ()
I suspect that is because the non active Xorg server doesn't answer requests until it gets active again. As a result the boinc_client process gets fully stuck and unit processing eventually stops, as computing processes eventually get into zombie state when they finish their work.