Setting idlers via penctl causing pen segmentation fault

[ifduyue]

Running pen: -u nobody -frdd -C 20000 -b 10 8080 127.0.0.1:8000
In another terminal: penctl 127.0.0.1:20000 idlers 1
And then segmentation fault.

$ gdb ./pen
(gdb)  r -u nobody -frdd -C 20000 -b 10 8080 127.0.0.1:8000
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
2019-03-24 20:29:59: read_cfg((null))
2019-03-24 20:29:59: open_listener(20000)
2019-03-24 20:29:59: pen_aton(0.0.0.0, 0x7fffffffd990)
2019-03-24 20:29:59: family = 2
socktype = 1
protocol = 6
addrlen = 16
sockaddr = 6414032
canonname = (null)
2019-03-24 20:29:59: socket returns 8, socket_errno=0
2019-03-24 20:29:59: local address=[0.0.0.0:20000]
2019-03-24 20:29:59: open_listener(8080)
2019-03-24 20:29:59: pen_aton(0.0.0.0, 0x7fffffffd990)
2019-03-24 20:29:59: family = 2
socktype = 1
protocol = 6
addrlen = 16
sockaddr = 6413296
canonname = (null)
2019-03-24 20:29:59: socket returns 9, socket_errno=0
2019-03-24 20:29:59: local address=[0.0.0.0:8080]
2019-03-24 20:29:59: init(2, 0x7fffffffdfd8); port = 8080
2019-03-24 20:29:59: Before: conns = (nil), connections_max = 0, clients = (nil), clients_max = 0
2019-03-24 20:29:59: expand_conntable(500)
2019-03-24 20:29:59: After: conns = 0x61e180, connections_max = 500, clients = 0x7ffff7f89010, clients_max = 2048
2019-03-24 20:29:59: server[0] = 127.0.0.1:8000
2019-03-24 20:29:59: n = 2, address = 127.0.0.1, pno = 8000, maxc1 = 0, hard = 0, weight = 0, prio = 0, proto = 1
2019-03-24 20:29:59: pen_aton(127.0.0.1, 0x61dd38)
2019-03-24 20:29:59: family = 2
socktype = 1
protocol = 6
addrlen = 16
sockaddr = 6413856
canonname = (null)
2019-03-24 20:29:59: pen 0.35.0 starting
2019-03-24 20:29:59: servers:
2019-03-24 20:29:59:  0 127.0.0.1:8000:0:0:0:0
2019-03-24 20:29:59: Run as user nobody
2019-03-24 20:29:59: epoll_create1 returns 10
2019-03-24 20:29:59: epoll_event_add(fd=9, events=65536)
2019-03-24 20:29:59: epoll_event_ctl(fd=9, events=65536, op=1)
2019-03-24 20:29:59: epoll_event_add(fd=8, events=65536)
2019-03-24 20:29:59: epoll_event_ctl(fd=8, events=65536, op=1)
2019-03-24 20:29:59: mainloop()
2019-03-24 20:29:59: epoll_event_arm(fd=9, events=65536)
2019-03-24 20:29:59: epoll_event_ctl(fd=9, events=65536, op=3)
2019-03-24 20:29:59: epoll_event_wait()
2019-03-24 20:30:02: epoll_wait returns 0
2019-03-24 20:30:02: After event_wait()
2019-03-24 20:30:02: epoll_event_fd(revents=0x7fffffffdd84)
2019-03-24 20:30:02: epoll_event_wait()
2019-03-24 20:30:03: epoll_wait returns 1
2019-03-24 20:30:03: After event_wait()
2019-03-24 20:30:03: epoll_event_fd(revents=0x7fffffffdd84)
2019-03-24 20:30:03: event_fd returns fd=8, events=65536
2019-03-24 20:30:03: check_control_socket()
2019-03-24 20:30:03: match_acl_ipv4(0, 16777343)
2019-03-24 20:30:03: do_cmd(idlers 1, 0x404320, 0x7fffffffcd1c)
2019-03-24 20:30:03: epoll_event_fd(revents=0x7fffffffdd84)
2019-03-24 20:30:03: incrementing connections_used to 1 for connection 0
2019-03-24 20:30:03: store_conn: conn = 0, downfd = -1, connections_used = 1
2019-03-24 20:30:03: Trying server 0 for connection 0 at time 1553430603
2019-03-24 20:30:03: socket returns 11, socket_errno=0
2019-03-24 20:30:03: Connecting to 127.0.0.1
2019-03-24 20:30:03: Family: AF_INET
2019-03-24 20:30:03: Port: 8000
2019-03-24 20:30:03: Address: 127.0.0.1
2019-03-24 20:30:03: connect (upfd = 11) returns -1, errno = 115, socket_errno = 115
2019-03-24 20:30:03: epoll_event_add(fd=11, events=131072)
2019-03-24 20:30:03: epoll_event_ctl(fd=11, events=131072, op=1)
2019-03-24 20:30:03: Pending connect to server 0
conns[0].client = -1
conns[0].server = -3
2019-03-24 20:30:03: Setting server 0 for client -1

Program received signal SIGSEGV, Segmentation fault.
0x000000000040e79f in try_server (index=0, conn=conn@entry=0) at server.c:424
424             clients[client].server = index;
Missing separate debuginfos, use: debuginfo-install glibc-2.17-260.el7_6.3.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.15.1-37.el7_6.x86_64 libcom_err-1.42.9-13.el7.x86_64 libselinux-2.5-14.1.el7.x86_64 openssl-libs-1.0.2k-16.el7.x86_64 pcre-8.32-17.el7.x86_64 sssd-client-1.16.2-13.el7_6.5.x86_64 zlib-1.2.7-18.el7.x86_64
(gdb) list
419                     close(upfd);
420                     return 0;
421             }
422             conns[conn].server = index;
423             DEBUG(2, "Setting server %d for client %d", index, client);
424             clients[client].server = index;
425             current = index;
426             conns[conn].upfd = upfd;
427             fd2conn_set(upfd, conn);
428             return 1;
(gdb) p client
$1 = -1

[ifduyue]

Another bug relating to idlers -- can't reduce idlers.
Reproduce:

export CONTROL_PORT=20000 
seq 1000 | xargs -I{} -P1 -- bash -c 'penctl 127.0.0.1:$CONTROL_PORT idlers ${RANDOM:0:2}'
seq 3 | xargs -I{} -P1 -- bash -c 'penctl 127.0.0.1:$CONTROL_PORT idlers;sleep 2'