Coredump

Core Dump Analysis

Description

Post-mortem debugging using core dumps for crashes that occur before gdbserver can catch them.

When to Use

• Crashes during very early startup
• Crashes before gdbserver fully initializes
• When you need to reproduce and analyze offline
• Segfaults, aborts, or other fatal signals

Enable Core Dumps

# Enable for current session
ulimit -c unlimited

# Verify
ulimit -c

Generate and Analyze

# Run until crash
./ikigai
# Produces: core or core.<pid>

# Analyze
gdb ./ikigai core

Key Commands

bt                  # Backtrace - where it crashed
bt full             # Backtrace with local variables
frame N             # Select stack frame
info locals         # Variables in current frame
print var           # Inspect variable
list                # Source at crash point
info registers      # CPU state at crash
x/20x $sp           # Examine stack memory

Finding the Core File

# Check core pattern
cat /proc/sys/kernel/core_pattern

# Common locations
ls -la core*
ls -la /var/crash/

Workflow

1. Enable core dumps: ulimit -c unlimited
2. Run app until crash
3. Load core: gdb ./ikigai core
4. Get backtrace: bt full
5. Inspect frames and variables

References

• GDB manual: https://sourceware.org/gdb/current/onlinedocs/gdb/
• See gdbserver.md for live debugging