[squid-users] squid crash: ERROR: system call failure while accepting a TLS connection

[Martin A. Brooks]

Hi folks,

I am running 3 squid instances behind a load balancer.  It was running 
fine for a couple of weeks but but there were suddenly tens of thousands 
of this sort of message in the log:


squid[507015]: ERROR: system call failure while accepting a TLS 
connection on conn705596 local=[redacted]:3128 remote=[redacted]:34830 
FD 56 flags=1: 0xaaaae5711490*1


The eventually exit looks like this in the log:


squid[507015]: ERROR: system call failure while accepting a TLS 
connection on conn17735186 local=[redacted]:3128 remote=[redacted]:44828 
FD 97 flags=1: 0xaaaae7384760*1
                                                        current master 
transaction: master59891221
squid[507015]: logfileHandleWrite: daemon:/var/log/squid/access.log: 
error writing ((32) Broken pipe)
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1
squid[507015]: Closing HTTP(S) port [::]:3128
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1
squid[507015]: storeDirWriteCleanLogs: Starting...
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1
squid[507015]:   Finished.  Wrote 0 entries.
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1
squid[507015]:   Took 0.00 seconds (  0.00 entries/sec).
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1
squid[507015]: FATAL: I don't handle this error well!
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1
squid[507015]: Squid Cache (Version 5.7): Terminated abnormally.
                                                        connection: 
conn17735104 local=[redacted]:3128 remote=[redacted]:44550 FD 75 flags=1



systemd tried to restart squid a few times, but repeated failures meant 
it eventually gave up. This is squid-openssl as packaged by Debian on 
ARM64:

# squid --version
Squid Cache: Version 5.7
Service Name: squid
Debian linux

This binary uses OpenSSL 3.0.15 3 Sep 2024. configure options:  
'--build=aarch64-linux-gnu' '--prefix=/usr' 
'--includedir=${prefix}/include' '--mandir=${prefix}/share/man' 
'--infodir=${prefix}/share/info' '--sysconfdir=/etc' 
'--localstatedir=/var' '--disable-option-checking' 
'--disable-silent-rules' '--libdir=${prefix}/lib/aarch64-linux-gnu' 
'--runstatedir=/run' '--disable-maintainer-mode' 
'--disable-dependency-tracking' 'BUILDCXXFLAGS=-g -O2 
-ffile-prefix-map=/build/reproducible-path/squid-5.7=. 
-fstack-protector-strong -Wformat -Werror=format-security 
-Wno-error=deprecated-declarations -Wdate-time -D_FORTIFY_SOURCE=2 
-Wl,-z,relro -Wl,-z,now ' 'BUILDCXX=g++' 
'--with-build-environment=default' '--enable-build-info=Debian linux' 
'--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,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,time_quota,unix_group,wbinfo_group' 
'--enable-security-cert-validators=fake' 
'--enable-storeid-rewrite-helpers=file' 
'--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=/run/squid.pid' 
'--with-filedescriptors=65536' '--with-large-files' 
'--with-default-user=proxy' '--enable-linux-netfilter' '--with-systemd' 
'--with-openssl' '--enable-ssl-crtd' 'build_alias=aarch64-linux-gnu' 
'CFLAGS=-g -O2 -ffile-prefix-map=/build/reproducible-path/squid-5.7=. 
-fstack-protector-strong -Wformat -Werror=format-security 
-Wno-error=deprecated-declarations' 'LDFLAGS=-Wl,-z,relro -Wl,-z,now ' 
'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 
-ffile-prefix-map=/build/reproducible-path/squid-5.7=. 
-fstack-protector-strong -Wformat -Werror=format-security 
-Wno-error=deprecated-declarations'


It looks like all three of the squid instances blew up at nearly the 
same time.

Any ideas what could be going on here?


Regards


Martin.