Thread: Random memory related errors on live postgres 14.13 instance on Ubuntu 22.04 LTS

Hello everyone, I’ve been using postgres for over 25 years now and never had any major issues which were not caused by my own stupidity. In the last 24 hours however I’ve had a number of issues on one client's server which I assume are a bug in postgres or a possible hardware issue (they are running on a Linode) but I need some clarification and would welcome advice on how to proceed. I will also forward this mail to Linode support to ask them to check for any memory issues they can detect. 

This particular Postgres is running on Ubuntu LTS 22.04 and has the following version information:

```

PostgreSQL 14.13 (Ubuntu 14.13-0ubuntu0.22.04.1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, 64-bit

```

The quick summary is that over a 24 hour period I had the following errors appear in the postgres logs at different times causing the system processes to restart:

• stuck spinlock detected 
• free(): corrupted unsorted chunks 
• double free or corruption (!prev)
• corrupted size vs. prev_size 
• corrupted double-linked list 
• *** stack smashing detected ***: terminated 
• Segmentation fault 

Here’s the more detailed breakdown. 

On Monday evening this week, the following event occurred on the server

```

2024-10-28 18:12:47.145 GMT [575437] xxx@xxx PANIC: stuck spinlock detected at LWLockWaitListLock, ./build/../src/backend/storage/lmgr/lwlock.c:913

```

Followed by:

```

2024-10-28 18:12:47.249 GMT [1880289] LOG: terminating any other active server processes

2024-10-28 18:12:47.284 GMT [1880289] LOG: all server processes terminated; reinitializing

```

And eventually

```

2024-10-28 18:12:48.474 GMT [575566] xxx@xxx FATAL: the database system is in recovery mode

2024-10-28 18:12:48.476 GMT [575550] LOG: database system was not properly shut down; automatic recovery in progress

2024-10-28 18:12:48.487 GMT [575550] LOG: redo starts at DD/405E83A8

2024-10-28 18:12:48.487 GMT [575550] LOG: invalid record length at DD/405EF818: wanted 24, got 0

2024-10-28 18:12:48.487 GMT [575550] LOG: redo done at DD/405EF7E0 system usage: CPU: user: 0.00 s, system: 0.00 s, elapsed: 0.00 s

2024-10-28 18:12:48.515 GMT [1880289] LOG: database system is ready to accept connections

```

This wasn’t noticed by myself or any users as they tend to all be finished by 17:30.  However later,

```

2024-10-28 20:27:15.258 GMT [611459] xxx@xxx LOG: unexpected EOF on client connection with an open transaction

2024-10-28 21:01:05.934 GMT [620373] xxx@xxxx LOG: unexpected EOF on client connection with an open transaction

free(): corrupted unsorted chunks

2024-10-28 21:15:02.203 GMT [1880289] LOG: server process (PID 623803) was terminated by signal 6: Aborted

2024-10-28 21:15:02.204 GMT [1880289] LOG: terminating any other active server processes

```

This time it could not recover and I didn’t notice until early the next morning whilst doing some routine checks.

```

2024-10-28 21:15:03.643 GMT [623807] LOG: database system was not properly shut down; automatic recovery in progress

2024-10-28 21:15:03.655 GMT [623807] LOG: redo starts at DD/47366740

2024-10-28 21:15:03.663 GMT [623807] LOG: invalid record length at DD/475452A0: wanted 24, got 0

2024-10-28 21:15:03.663 GMT [623807] LOG: redo done at DD/47545268 system usage: CPU: user: 0.00 s, system: 0.00 s, elapsed: 0.00 s

2024-10-28 21:15:03.682 GMT [623829] xxx@xxx FATAL: the database system is in recovery mode

double free or corruption (!prev)

2024-10-28 21:15:03.832 GMT [1880289] LOG: startup process (PID 623807) was terminated by signal 6: Aborted

2024-10-28 21:15:03.832 GMT [1880289] LOG: aborting startup due to startup process failure

2024-10-28 21:15:03.835 GMT [1880289] LOG: database system is shut down

```

When I noticed in the morning it was able to start without an issue. From googling it appeared to be a memory issue and I wondered if the problem was sorted now the server process had stopped completely and restarted. The problem was not sorted although all the above errors were recovered from automatically without any input from myself or the client’s noticing.

```

corrupted size vs. prev_size

2024-10-29 09:55:24.417 GMT [894747] LOG: background worker "parallel worker" (PID 947642) was terminated by signal 6: Aborted

```

```

corrupted double-linked list

2024-10-29 13:14:28.322 GMT [894747] LOG: background worker "parallel worker" (PID 1019071) was terminated by signal 6: Aborted

```

```

*** stack smashing detected ***: terminated

2024-10-28 15:24:30.331 GMT [1880289] LOG: background worker "parallel worker" (PID 528630) was terminated by signal 6: A\ borted

```

```

2024-10-28 15:40:26.617 GMT [1880289] LOG: background worker "parallel worker" (PID 533515) was terminated by signal 11: \

Segmentation fault

2024-10-28 15:40:26.617 GMT [1880289] DETAIL: Failed process was running: SELECT "formula_line".id FROM "formul\

```

I rebooted the server at 18:30 and have had no further issues so far, although work has yet to start. When rebooting the server, postgres seemed to take a long time to terminate.

Now there is one odd thing that has been happening recently. Due to a bug in my code I've had more deadlocks than would normally be expected. 

```

2024-10-29 19:26:51.680 GMT [71152] xxx@xxx ERROR:  could not serialize access due to concurrent update

```

I believe I have fixed that bug in my code this morning and the errors above did not seem to coincide with the errors appearing but I'm raising it in case related. 

Comments and insights are warmly welcomed. 

Best regards

Ian Cottee

BINDIR = /usr/lib/postgresql/14/bin                                                                                                                                                                                         
DOCDIR = /usr/share/doc/postgresql-doc-14                                                                                                                                                                                   
HTMLDIR = /usr/share/doc/postgresql-doc-14                                                                                                                                                                                  
INCLUDEDIR = /usr/include/postgresql                                                                                                                                                                                        
PKGINCLUDEDIR = /usr/include/postgresql                                                                                                                                                                                     
INCLUDEDIR-SERVER = /usr/include/postgresql/14/server                                                                                                                                                                       
LIBDIR = /usr/lib/x86_64-linux-gnu                                                                                                                                                                                          
PKGLIBDIR = /usr/lib/postgresql/14/lib                                                                                                                                                                                      
LOCALEDIR = /usr/share/locale                                                                                                                                                                                               
MANDIR = /usr/share/postgresql/14/man                                                                                                                                                                                       
SHAREDIR = /usr/share/postgresql/14                                                                                                                                                                                         
SYSCONFDIR = /etc/postgresql-common                                                                                                                                                                                         
PGXS = /usr/lib/postgresql/14/lib/pgxs/src/makefiles/pgxs.mk                                                                                                                                                                
CONFIGURE =  '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--disable-option-checki
ng' '--disable-silent-rules' '--libdir=${prefix}/lib/x86_64-linux-gnu' '--runstatedir=/run' '--disable-maintainer-mode' '--disable-dependency-tracking' '--with-tcl' '--with-perl' '--with-python' '--with-pam' '--with-open
ssl' '--with-libxml' '--with-libxslt' '--mandir=/usr/share/postgresql/14/man' '--docdir=/usr/share/doc/postgresql-doc-14' '--sysconfdir=/etc/postgresql-common' '--datarootdir=/usr/share/' '--datadir=/usr/share/postgresql
/14' '--bindir=/usr/lib/postgresql/14/bin' '--libdir=/usr/lib/x86_64-linux-gnu/' '--libexecdir=/usr/lib/postgresql/' '--includedir=/usr/include/postgresql/' '--with-extra-version= (Ubuntu 14.13-0ubuntu0.22.04.1)' '--enab
le-nls' '--enable-thread-safety' '--enable-debug' '--enable-dtrace' '--disable-rpath' '--with-uuid=e2fs' '--with-gnu-ld' '--with-gssapi' '--with-ldap' '--with-pgport=5432' '--with-system-tzdata=/usr/share/zoneinfo' 'AWK=
mawk' 'MKDIR_P=/bin/mkdir -p' 'PROVE=/usr/bin/prove' 'PYTHON=/usr/bin/python3' 'TAR=/bin/tar' 'XSLTPROC=xsltproc --nonet' 'CFLAGS=-g -O2 -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong 
-Wformat -Werror=format-security -fno-omit-frame-pointer' 'LDFLAGS=-Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -flto=auto -Wl,-z,relro -Wl,-z,now' '--enable-tap-tests' '--with-icu' '--with-llvm' 'LLVM_CONFIG=/u
sr/bin/llvm-config-14' 'CLANG=/usr/bin/clang-14' '--with-lz4' '--with-systemd' '--with-selinux' 'build_alias=x86_64-linux-gnu' 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 -flto=auto -ffat-lto-objects -flt
o=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security'                                                                                                                                         
CC = gcc                                                                                                                                                                                                                    
CPPFLAGS = -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -I/usr/include/libxml2                                                                                                                                             
CFLAGS = -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type -Wformat-security -fno-strict-aliasing
 -fwrapv -fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation -g -g -O2 -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security -fno-omit
-frame-pointer                                                                                                                                                                                                              
CFLAGS_SL = -fPIC                                                                                                                                                                                                           
LDFLAGS = -Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -flto=auto -Wl,-z,relro -Wl,-z,now -L/usr/lib/llvm-14/lib -Wl,--as-needed                                                                                   
LDFLAGS_EX =                                                                                                                                                                                                                
LDFLAGS_SL =                                                                                                                                                                                                                
LIBS = -lpgcommon -lpgport -lselinux -llz4 -lxslt -lxml2 -lpam -lssl -lcrypto -lgssapi_krb5 -lz -lreadline -lm                                                                                                              
VERSION = PostgreSQL 14.13 (Ubuntu 14.13-0ubuntu0.22.04.1)