[root@arch-zfs-test ~]# coredumpctl gdb 1403 PID: 1403 (xl) UID: 0 (root) GID: 0 (root) Signal: 11 (SEGV) Timestamp: Wed 2017-05-03 02:30:28 EEST (13min ago) Command Line: /usr/bin/xl devd Executable: /usr/bin/xl Control Group: /system.slice/xendriverdomain.service Unit: xendriverdomain.service Slice: system.slice Boot ID: 563263b57f1245c9b4266b42d5ca3dc5 Machine ID: c0f2ee0d91c44644a2ea229db2047149 Hostname: arch-zfs-test Storage: /var/lib/systemd/coredump/core.xl.0.563263b57f1245c9b4266b42d5ca3dc5.1403.1493767828000000000000.lz4 Message: Process 1403 (xl) of user 0 dumped core. Stack trace of thread 1403: #0 0x00007f49bf42519d search_for_guest (libxenlight.so.4.8) #1 0x00007f49bf425931 backend_watch_callback (libxenlight.so.4.8) #2 0x00007f49bf4629da watchfd_callback (libxenlight.so.4.8) #3 0x00007f49bf464612 fd_occurs (libxenlight.so.4.8) #4 0x00007f49bf4646c4 afterpoll_internal (libxenlight.so.4.8) #5 0x00007f49bf465dfd eventloop_iteration (libxenlight.so.4.8) #6 0x00007f49bf466bb1 libxl__ao_inprogress (libxenlight.so.4.8) #7 0x00007f49bf4261dc libxl_device_events_handler (libxenlight.so.4.8) #8 0x0000000000423258 main_devd (xl) #9 0x0000000000408e05 main (xl) #10 0x00007f49bea49511 __libc_start_main (libc.so.6) #11 0x000000000040800a _start (xl) Stack trace of thread 1404: #0 0x00007f49bedddf7d read (libpthread.so.0) #1 0x00007f49be1b5c3d read_all (libxenstore.so.3.0) #2 0x00007f49be1b76ca read_message (libxenstore.so.3.0) #3 0x00007f49be1b7a1f read_thread (libxenstore.so.3.0) #4 0x00007f49bedd42e7 start_thread (libpthread.so.0) #5 0x00007f49beb1554f __clone (libc.so.6) GNU gdb (GDB) 7.12.1 Copyright (C) 2017 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-pc-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: . Find the GDB manual and other documentation resources online at: . For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from /usr/bin/xl...done. [New LWP 1403] [New LWP 1404] [Thread debugging using libthread_db enabled] Using host libthread_db library "/usr/lib/libthread_db.so.1". Core was generated by `/usr/bin/xl devd'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x00007f49bf42519d in search_for_guest (ddomain=0x7ffc601e7130, domid=0) at libxl.c:3688 3688 if (dguest->domid == domid) [Current thread is 1 (Thread 0x7f49bfa75fc0 (LWP 1403))] (gdb) backtrace full #0 0x00007f49bf42519d in search_for_guest (ddomain=0x7ffc601e7130, domid=0) at libxl.c:3688 dguest = 0x31352f302f646276 #1 0x00007f49bf425931 in backend_watch_callback (egc=0x7ffc601e7060, watch=0x7ffc601e7138, watch_path=0x2188560 "/local/domain/1/backend", event_path=0x218ac90 "/local/domain/1/backend/vbd/0/51728/online") at libxl.c:3874 ddomain = 0x7ffc601e7130 nested_ao = 0x218ab80 ao = 0x218ab80 gc = 0x218abc0 p = 0x218ac33 "" path = 0x218ac10 "/local/domain/1/backend/vbd/0/51728" sstate = 0x7f49b40012b0 "5" sonline = 0x7f49b4001290 "0" state = 5 online = 0 rc = 0 num_devs = 0 dev = 0x2188bf0 ddev = 0x0 dguest = 0x0 free_ao = false ---Type to continue, or q to quit--- __func__ = "backend_watch_callback" #2 0x00007f49bf4629da in watchfd_callback (egc=0x7ffc601e7060, ev=0x218a8a8, fd=16, events=1, revents=1) at libxl_event.c:574 token = 0x218acbb "3/0" w = 0x7ffc601e7138 event = 0x218ac80 epath = 0x218ac90 "/local/domain/1/backend/vbd/0/51728/online" slotnum = 3 counterval = 0 rc = 2 gc = 0x7ffc601e7060 __func__ = "watchfd_callback" #3 0x00007f49bf464612 in fd_occurs (egc=0x7ffc601e7060, efd=0x218a8a8, revents_ign=1) at libxl_event.c:1200 revents_current = 1 #4 0x00007f49bf4646c4 in afterpoll_internal (egc=0x7ffc601e7060, poller=0x2189da0, nfds=2, fds=0x218a0e0, now=...) at libxl_event.c:1265 revents = 1 gc = 0x7ffc601e7060 efd = 0x218a8a8 __func__ = "afterpoll_internal" __PRETTY_FUNCTION__ = "afterpoll_internal" #5 0x00007f49bf465dfd in eventloop_iteration (egc=0x7ffc601e7060, ---Type to continue, or q to quit--- poller=0x2189da0) at libxl_event.c:1711 gc = 0x7ffc601e7060 rc = 0 nfds = 2 now = {tv_sec = 1493767828, tv_usec = 93099} timeout = -1 __func__ = "eventloop_iteration" #6 0x00007f49bf466bb1 in libxl__ao_inprogress (ao=0x2188350, file=0x7f49bf4a979b "libxl.c", line=4014, func=0x7f49bf4acd00 <__func__.21414> "libxl_device_events_handler") at libxl_event.c:1997 egc = {gc = {alloc_maxsize = 0, alloc_ptrs = 0x0, owner = 0x218a7b0}, occurred_for_callback = {tqh_first = 0x0, tqh_last = 0x7ffc601e7078}, aos_for_callback = {tqh_first = 0x0, tqh_last = 0x7ffc601e7088}, aops_for_callback = {tqh_first = 0x0, tqh_last = 0x7ffc601e7098}} gc = 0x2188390 rc = 0 __PRETTY_FUNCTION__ = "libxl__ao_inprogress" __func__ = "libxl__ao_inprogress" #7 0x00007f49bf4261dc in libxl_device_events_handler (ctx=0x218a7b0, ao_how=0x0) at libxl.c:4014 ao__ctx = 0x218a7b0 ---Type to continue, or q to quit--- ao__rc = 0 ao = 0x2188350 __func__ = "libxl_device_events_handler" egc = {{gc = {alloc_maxsize = 0, alloc_ptrs = 0x0, owner = 0x218a7b0}, occurred_for_callback = {tqh_first = 0x0, tqh_last = 0x7ffc601e7178}, aos_for_callback = {tqh_first = 0x0, tqh_last = 0x7ffc601e7188}, aops_for_callback = { tqh_first = 0x0, tqh_last = 0x7ffc601e7198}}} gc = 0x2188390 rc = 0 domid = 1 ddomain = {ao = 0x2188350, watch = { path = 0x2188560 "/local/domain/1/backend", callback = 0x7f49bf425703 , slotnum = 3, counterval = 0}, guests = {slh_first = 0x2189f70}} be_path = 0x2189d80 "/local/domain/1/backend" kinds = 0x0 domains = 0x0 devs = 0x0 sstate = 0xffff000000000000 state_path = 0x0 state = 0 ---Type to continue, or q to quit--- nkinds = 4294967295 ndomains = 4294901760 ndevs = 6778732 i = -1078873872 j = 0 k = 0 __PRETTY_FUNCTION__ = "libxl_device_events_handler" #8 0x0000000000423258 in main_devd (argc=1, argv=0x7ffc601e7390) at xl_cmdimpl.c:9059 ret = 0 opt = -1 daemonize = 1 pidfile = 0x0 opts = {{name = 0x42d3e5 "pidfile", has_arg = 1, flag = 0x0, val = 112}, {name = 0x429059 "help", has_arg = 0, flag = 0x0, val = 104}, {name = 0x0, has_arg = 0, flag = 0x0, val = 0}, { name = 0x0, has_arg = 0, flag = 0x0, val = 0}} #9 0x0000000000408e05 in main (argc=1, argv=0x7ffc601e7390) at xl.c:364 opt = -1 cmd = 0x7ffc601e8f5b "devd" cspec = 0x6363d0 ret = 0 config_data = 0x2187f20 ---Type to continue, or q to quit--- config_len = 1303