Why does squid crash?

Question

linux

OS - Ubuntu Server 16.04 on VPS
uname -a

Linux andrewg 2.6.32-042stab108.5 #1 SMP Wed Jun 17 20:20:17 MSK 2015 x86_64 x86_64 x86_64 GNU/Linux

Config file ( grep -v "^$\|^#" /etc/squid/squid.conf )

auth_param basic realm ***?
auth_param basic program /etc/webmin/squid/squid-auth.pl /etc/webmin/squid/users
acl Auth proxy_auth REQUIRED
http_access allow Auth
http_access deny all
http_port ****
tcp_outgoing_address ***.***.***.***
cache_dir ufs /var/spool/squid3 256 16 256
cache_log /var/log/squid/squid.log
coredump_dir /var/spool/squid3
pinger_enable off
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern -i (/cgi-bin/|\?) 0     0%      0
refresh_pattern (Release|Packages(.gz)*)$      0       20%     2880
refresh_pattern .               0       20%     4320
cache_effective_user proxy
dns_v4_first on
cache_effective_group proxy
via off
forwarded_for delete

As an authorization program, what webmin provides is used.
squid -v

Squid Cache: Version 3.5.12
Service Name: squid
Ubuntu linux
configure options:  '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--libexecdir=${prefix}/lib/squid3' '--srcdir=.' '--disable-maintainer-mode' '--disable-dependency-tracking' '--disable-silent-rules' 'BUILDCXXFLAGS=-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' '--datadir=/usr/share/squid' '--sysconfdir=/etc/squid' '--libexecdir=/usr/lib/squid' '--mandir=/usr/share/man' '--enable-inline' '--disable-arch-native' '--enable-async-io=8' '--enable-storeio=ufs,aufs,diskd,rock' '--enable-removal-policies=lru,heap' '--enable-delay-pools' '--enable-cache-digests' '--enable-icap-client' '--enable-follow-x-forwarded-for' '--enable-auth-basic=DB,fake,getpwnam,LDAP,NCSA,NIS,PAM,POP3,RADIUS,SASL,SMB' '--enable-auth-digest=file,LDAP' '--enable-auth-negotiate=kerberos,wrapper' '--enable-auth-ntlm=fake,smb_lm' '--enable-external-acl-helpers=file_userip,kerberos_ldap_group,LDAP_group,session,SQL_session,unix_group,wbinfo_group' '--enable-url-rewrite-helpers=fake' '--enable-eui' '--enable-esi' '--enable-icmp' '--enable-zph-qos' '--enable-ecap' '--disable-translation' '--with-swapdir=/var/spool/squid' '--with-logdir=/var/log/squid' '--with-pidfile=/var/run/squid.pid' '--with-filedescriptors=65536' '--with-large-files' '--with-default-user=proxy' '--enable-build-info=Ubuntu linux' '--enable-linux-netfilter' 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wall' 'LDFLAGS=-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security'

Here are the logs
cat /var/log/syslog | grep squid

Aug  5 12:19:34 andrew squid[20873]: Squid Parent: (squid-1) process 20875 started
Aug  5 22:24:48 andrew squid[20873]: Squid Parent: (squid-1) process 20875 exited due to signal 9 with status 0

cat /var/log/squid/squid.log (I specified this file in the cache_log variable)

2016/08/05 12:19:34 kid1| Set Current Directory to /var/spool/squid3
2016/08/05 12:19:34 kid1| Starting Squid Cache version 3.5.12 for x86_64-pc-linux-gnu...
2016/08/05 12:19:34 kid1| Service Name: squid
2016/08/05 12:19:34 kid1| Process ID 20875
2016/08/05 12:19:34 kid1| Process Roles: worker
2016/08/05 12:19:34 kid1| With 65535 file descriptors available
2016/08/05 12:19:34 kid1| Initializing IP Cache...
2016/08/05 12:19:34 kid1| DNS Socket created at [::], FD 6
2016/08/05 12:19:34 kid1| DNS Socket created at 0.0.0.0, FD 8
2016/08/05 12:19:34 kid1| Adding nameserver 8.8.8.8 from /etc/resolv.conf
2016/08/05 12:19:34 kid1| Adding nameserver 8.8.4.4 from /etc/resolv.conf
2016/08/05 12:19:34 kid1| helperOpenServers: Starting 0/20 'squid-auth.pl' processes
2016/08/05 12:19:34 kid1| helperOpenServers: No 'squid-auth.pl' processes needed.
2016/08/05 12:19:34 kid1| Logfile: opening log daemon:/var/log/squid/access.log
2016/08/05 12:19:34 kid1| Logfile Daemon: opening log /var/log/squid/access.log
2016/08/05 12:19:34 kid1| Unlinkd pipe opened on FD 14
2016/08/05 12:19:34 kid1| Local cache digest enabled; rebuild/rewrite every 3600/3600 sec
2016/08/05 12:19:34 kid1| Store logging disabled
2016/08/05 12:19:34 kid1| Swap maxSize 262144 + 262144 KB, estimated 40329 objects
2016/08/05 12:19:34 kid1| Target number of buckets: 2016
2016/08/05 12:19:34 kid1| Using 8192 Store buckets
2016/08/05 12:19:34 kid1| Max Mem  size: 262144 KB
2016/08/05 12:19:34 kid1| Max Swap size: 262144 KB
2016/08/05 12:19:35 kid1| Rebuilding storage in /var/spool/squid3 (dirty log)
2016/08/05 12:19:35 kid1| Using Least Load store dir selection
2016/08/05 12:19:35 kid1| Set Current Directory to /var/spool/squid3
2016/08/05 12:19:36 kid1| Finished loading MIME types and icons.
2016/08/05 12:19:36 kid1| HTCP Disabled.
2016/08/05 12:19:36 kid1| Squid plugin modules loaded: 0
2016/08/05 12:19:36 kid1| Adaptation support is off.
2016/08/05 12:19:36 kid1| Accepting HTTP Socket connections at local=[::]:****remote=[::] FD 17 flags=9
2016/08/05 12:19:36 kid1| Store rebuilding is 21.44% complete
2016/08/05 12:19:36 kid1| Done reading /var/spool/squid3 swaplog (18653 entries)
2016/08/05 12:19:36 kid1| Finished rebuilding storage from disk.
2016/08/05 12:19:36 kid1|     12656 Entries scanned
2016/08/05 12:19:36 kid1|         9 Invalid entries.
2016/08/05 12:19:36 kid1|         0 With invalid flags.
2016/08/05 12:19:36 kid1|     11674 Objects loaded.
2016/08/05 12:19:36 kid1|         0 Objects expired.
2016/08/05 12:19:36 kid1|         0 Objects cancelled.
2016/08/05 12:19:36 kid1|       180 Duplicate URLs purged.
2016/08/05 12:19:36 kid1|       802 Swapfile clashes avoided.
2016/08/05 12:19:36 kid1|   Took 1.33 seconds (8777.01 objects/sec).
2016/08/05 12:19:36 kid1| Beginning Validation Procedure
2016/08/05 12:19:36 kid1|   Completed Validation Procedure
2016/08/05 12:19:36 kid1|   Validated 11674 Entries
2016/08/05 12:19:36 kid1|   store_swap_size = 385740.00 KB
2016/08/05 12:19:39 kid1| storeLateRelease: released 0 objects
2016/08/05 12:19:54 kid1| Starting new basicauthenticator helpers...
2016/08/05 12:19:54 kid1| helperOpenServers: Starting 1/20 'squid-auth.pl' processes
2016/08/05 12:59:36 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 12:59:36 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 12:59:36 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 13:41:15 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 13:41:15 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 13:41:15 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 14:35:50 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 14:35:50 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 14:35:50 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 15:35:20 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 15:35:20 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 15:35:20 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 16:33:30 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 16:33:30 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 16:33:30 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 17:46:46 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 17:46:46 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 17:46:46 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 18:49:29 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 18:49:29 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 18:49:29 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 19:31:31 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 19:31:31 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 19:31:31 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 20:12:16 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 20:12:16 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 20:12:16 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 21:02:22 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 21:02:22 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 21:02:22 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 22:17:24 kid1| Logfile: opening log stdio:/var/log/squid/netdb.state
2016/08/05 22:17:24 kid1| Logfile: closing log stdio:/var/log/squid/netdb.state
2016/08/05 22:17:24 kid1| NETDB state saved; 0 entries, 0 msec
2016/08/05 22:24:47 kid1| WARNING: basicauthenticator #Hlpr1 exited
2016/08/05 22:24:48 kid1| Too few basicauthenticator processes are running (need 1/20)
2016/08/05 22:24:48 kid1| Starting new helpers
2016/08/05 22:24:48 kid1| helperOpenServers: Starting 1/20 'squid-auth.pl' processes

Squid crashes regularly, every day or every other day, sometimes several times a day.
What could be the problem?

Answer 1

It falls after the fall of the authenticator. Check if it is correct and the paths are correct.
Perhaps it is possible to write debug information on this authenticator in order to find out the reason for its failure?