Hi! If something is running which is started from attach script, restarting of hotplugd fails because /dev/hotplug is occupied by child process.
Attached is the patch to fix this problem.
Index: usr.sbin/hotplugd/hotplugd.c =================================================================== RCS file: /cvs/src/usr.sbin/hotplugd/hotplugd.c,v retrieving revision 1.13 diff -u -p -r1.13 hotplugd.c --- usr.sbin/hotplugd/hotplugd.c 19 Nov 2015 06:05:40 -0000 1.13 +++ usr.sbin/hotplugd/hotplugd.c 25 Jul 2016 11:05:12 -0000 @@ -82,6 +82,7 @@ main(int argc, char *argv[]) if ((devfd = open(device, O_RDONLY)) == -1) err(1, "%s", device); + fcntl(devfd, F_SETFD, FD_CLOEXEC); bzero(&sact, sizeof(sact)); sigemptyset(&sact.sa_mask);