delv isc_app_ctxsuspend ctx->running ASSERTION

[Steve Egbert]

> Had an assertion error for `delv` utility in trying to perform suspend 
> thread.
> 
> Doesn't seem specific to any thing, argument-wise.
> 
> Environment:
> Linux 4.19
> Debian 10.3
> Custom built Bind v9.17.1
> 
> 
> bind9/lib/isc/app.c:422
> void
> isc_app_ctxsuspend(isc_appctx_t *ctx) {
>      REQUIRE(VALID_APPCTX(ctx));
> 
>      REQUIRE(atomic_load(&ctx->running));
> 
>      /*
>       * Don't send the reload signal if we're shutting down.
>       */
>      if (atomic_load_acquire(&ctx->shutdown_requested) == false) {
> 
> 
> Traceback:
> 
> # delv -v
> delv 9.17.1-dev
> 
Gdb reported:

root at ns1:~/admin/bind9/bind9/lib# exit
exit
(gdb) b isc_app_ctxsuspend
Breakpoint 1 at 0x7ffff7f7e020: isc_app_ctxsuspend. (2 locations)
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/local/bin/delv @ns1.egbert.net 
_pop3s._tcp.mx1.egbert.net. srv
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff752f700 (LWP 14643)]
[New Thread 0x7ffff6d04700 (LWP 14644)]
[New Thread 0x7ffff6503700 (LWP 14645)]
[New Thread 0x7ffff5517700 (LWP 14646)]
[New Thread 0x7ffff4cec700 (LWP 14647)]
[New Thread 0x7ffff44eb700 (LWP 14648)]
[Switching to Thread 0x7ffff5517700 (LWP 14646)]

Thread 5 "isc-worker0000" hit Breakpoint 1, isc_app_ctxsuspend (
     ctx=0x7ffff5518010) at app.c:420
420		REQUIRE(VALID_APPCTX(ctx));
(gdb) bt
#0  isc_app_ctxsuspend (ctx=0x7ffff5518010) at app.c:420
#1  0x00007ffff7cfc099 in process_answer (task=<optimized out>,
     event=<optimized out>) at getaddrinfo.c:908
#2  0x00007ffff7f9cb3b in dispatch (threadid=<optimized out>,
     manager=0x7ffff5519010) at task.c:1152
#3  run (queuep=<optimized out>) at task.c:1344
#4  0x00007ffff7cddfa3 in start_thread (arg=<optimized out>)
     at pthread_create.c:486
#5  0x00007ffff7c0e4cf in clone ()
     at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Who should I contact about this utility?  Github history shows two 
contributors to the lib/isc/app.c file:

* Ondřej Surý
* Evan Hunt