A backtrace on Ubuntu 18.10 on Linux 4.18.0-13-generic with 5.2.20 r125813:
```
(gdb) bt
#0 0x00007f08c4693357 in kill () at ../sysdeps/unix/syscall-template.S:78
#1 0x0000559d23710606 in crash (sig=11) at ../src/core/main.c:183
#2 <signal handler called>
#3 __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:62
#4 0x00007f08c449fef7 in message_append_basic (m=m@entry=0x559d24121590,
type=<optimized out>, p=0x100000000, stored=stored@entry=0x0)
at ../src/basic/string-util.h:36
#5 0x00007f08c44a04eb in sd_bus_message_append_basic (
m=m@entry=0x559d24121590, type=<optimized out>, p=<optimized out>)
at ../src/libsystemd/sd-bus/bus-message.c:1565
#6 0x00007f08c44a0959 in sd_bus_message_appendv (m=0x559d24121590,
types=<optimized out>, ap=ap@entry=0x7fffedec2ef0)
at ../src/libsystemd/sd-bus/bus-message.c:2358
#7 0x00007f08c44a0f39 in sd_bus_message_append (m=<optimized out>,
types=<optimized out>) at ../src/libsystemd/sd-bus/bus-message.c:2473
#8 0x0000559d2368caff in send_removed_signal (bus=0x559d23fff380,
userdata=0x559d240a0f20) at ../src/core/job.c:1565
#9 0x0000559d236fcf8f in bus_foreach_bus (m=0x559d23ee83f0, subscribed2=0x0,
send_message=0x559d2368ca50 <send_removed_signal>, userdata=0x559d240a0f20)
at ../src/core/dbus.c:1187
#10 0x0000559d2368ecd8 in bus_job_send_removed_signal (j=<optimized out>,
j=<optimized out>) at ../src/core/dbus-job.c:225
#11 0x0000559d2370e1de in manager_flush_finished_jobs (m=<optimized out>)
--Type <RET> for more, q to quit, c to continue without paging--
at ../src/core/manager.c:3359
#12 manager_reload (m=0x559d23ee83f0) at ../src/core/manager.c:3477
#13 invoke_main_loop (m=0x559d23ee83f0, ret_reexecute=0x7fffedec31ca,
ret_retval=0x7fffedec31cc, ret_shutdown_verb=<optimized out>,
ret_fds=0x7fffedec31d0, ret_switch_root_dir=0x7fffedec31f8,
ret_switch_root_init=0x7fffedec31f0, ret_error_message=0x7fffedec31e0)
at ../src/core/main.c:1661
#14 0x0000559d2366f610 in main (argc=<optimized out>, argv=0x7fffedec34a8)
at ../src/core/main.c:2415
```
A backtrace on Ubuntu 18.10 on Linux 4.18.0-13-generic with 5.2.20 r125813:
``` unix/syscall- template. S:78 core/main. c:183 x86_64/ multiarch/ strlen- avx2.S: 62 append_ basic (m=m@entry= 0x559d24121590, stored@ entry=0x0) basic/string- util.h: 36 message_ append_ basic ( entry=0x559d241 21590, type=<optimized out>, p=<optimized out>) libsystemd/ sd-bus/ bus-message. c:1565 message_ appendv (m=0x559d24121590, <optimized out>, ap=ap@entry= 0x7fffedec2ef0) libsystemd/ sd-bus/ bus-message. c:2358 message_ append (m=<optimized out>, <optimized out>) at ../src/ libsystemd/ sd-bus/ bus-message. c:2473 f380, 0x559d240a0f20) at ../src/ core/job. c:1565 message= 0x559d2368ca50 <send_removed_ signal> , userdata= 0x559d240a0f20) core/dbus. c:1187 send_removed_ signal (j=<optimized out>, core/dbus- job.c:225 flush_finished_ jobs (m=<optimized out>) core/manager. c:3359 core/manager. c:3477 0x7fffedec31ca, retval= 0x7fffedec31cc, ret_shutdown_ verb=<optimized out>, fds=0x7fffedec3 1d0, ret_switch_ root_dir= 0x7fffedec31f8, switch_ root_init= 0x7fffedec31f0, ret_error_ message= 0x7fffedec31e0) core/main. c:1661 34a8) core/main. c:2415
(gdb) bt
#0 0x00007f08c4693357 in kill () at ../sysdeps/
#1 0x0000559d23710606 in crash (sig=11) at ../src/
#2 <signal handler called>
#3 __strlen_avx2 () at ../sysdeps/
#4 0x00007f08c449fef7 in message_
type=<optimized out>, p=0x100000000, stored=
at ../src/
#5 0x00007f08c44a04eb in sd_bus_
m=m@
at ../src/
#6 0x00007f08c44a0959 in sd_bus_
types=
at ../src/
#7 0x00007f08c44a0f39 in sd_bus_
types=
#8 0x0000559d2368caff in send_removed_signal (bus=0x559d23ff
userdata=
#9 0x0000559d236fcf8f in bus_foreach_bus (m=0x559d23ee83f0, subscribed2=0x0,
send_
at ../src/
#10 0x0000559d2368ecd8 in bus_job_
j=<optimized out>) at ../src/
#11 0x0000559d2370e1de in manager_
--Type <RET> for more, q to quit, c to continue without paging--
at ../src/
#12 manager_reload (m=0x559d23ee83f0) at ../src/
#13 invoke_main_loop (m=0x559d23ee83f0, ret_reexecute=
ret_
ret_
ret_
at ../src/
#14 0x0000559d2366f610 in main (argc=<optimized out>, argv=0x7fffedec
at ../src/
```