assert in setup_random

We've started seeing an assert failing inside setup_random at line 537:

 528 static void setup_random()
 529 {
 530 #ifndef _WIN32          // TODO: better seed
 531     int seed;
 532     int fd = open("/dev/urandom", O_RDONLY);
 533     if (fd == -1) {
 534         seed = getpid();
 535     } else {
 536         int rc = read(fd, &seed, sizeof(seed));
 537         assert(rc == sizeof(seed));
 538         close(fd);
 539     }
 540     srandom(seed);
 541     srand48(seed);
 542 #endif

The core files show:

Program terminated with signal 6, Aborted.
#0 0x00007f9ff665a0d5 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#0 0x00007f9ff665a0d5 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007f9ff665d83b in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2 0x00007f9ff6652d9e in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#3 0x00007f9ff6652e42 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6
#4 0x00007f9ff8e4070a in setup_random () at src/zookeeper.c:476
#5 0x00007f9ff8e40d76 in resolve_hosts (zh=0x7f9fe14de400, hosts_in=0x7f9fd700f400 "10.26.200.6:2181,10.26.200.7:2181,10.26.200.8:2181", avec=0x7f9fd87fab60) at src/zookeeper.c:730
#6 0x00007f9ff8e40e87 in update_addrs (zh=0x7f9fe14de400) at src/zookeeper.c:801
#7 0x00007f9ff8e44176 in zookeeper_interest (zh=0x7f9fe14de400, fd=0x7f9fd87fac4c, interest=0x7f9fd87fac50, tv=0x7f9fd87fac80) at src/zookeeper.c:1980
#8 0x00007f9ff8e553f5 in do_io (v=0x7f9fe14de400) at src/mt_adaptor.c:379
#9 0x00007f9ff804de9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#10 0x00007f9ff671738d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#11 0x0000000000000000 in ?? ()

I'm not sure what the underlying cause of this is... But POSIX always allows for a short read(2), and any program MUST check for short reads...

Has anyone else encountered this issue? We are seeing it rather frequently which is concerning.