Linux / Server

Segmentation fault (core dumped)

A program crashed by accessing memory it shouldn't — a bug in the binary or a bad library.

What it looks like

Segmentation fault (core dumped)
app[4121]: segfault at 0 ip 00007f3a2c1b4e10 sp 00007ffd9a3c8f20 error 4 in libfoo.so.1

What does "Segmentation fault (core dumped)" mean?

Printed by the shell, and logged by the kernel (dmesg, journalctl), when a native program touches memory it is not allowed to. In scripting languages it means native code crashed — the interpreter itself or a compiled extension — not your script.

What causes "Segmentation fault (core dumped)"?

• A bug in native code (null/invalid pointer).
• Incompatible/corrupt shared library.
• Stack overflow in native code.

How do I confirm the cause?

1. Check dmesg or journalctl for the kernel’s segfault line, which names the program and often the library it crashed in.
2. Get a backtrace from the core dump (coredumpctl gdb, or gdb program core) to see the exact function.
3. If it started after an upgrade, suspect a mismatched library or a compiled extension built for another version.

How do I fix "Segmentation fault (core dumped)"?

• Reproduce and get a backtrace (gdb / coredumpctl).
• Update or reinstall the program and its libraries.
• Report it upstream with the backtrace if it's not your code.

How do I stop it happening again?

• Rebuild or reinstall native extensions after upgrading the language runtime.
• Keep programs and their libraries from the same package source and version.

Got a different error? Paste it into the Explain This Error tool → Identifies the family and the fix — runs locally, nothing uploaded.

Related errors