kernel panic
also: oops, kernel oops
A kernel panic is a critical error in the Linux kernel that causes the system to halt and display an error message, unable to recover automatically. It typically indicates a serious hardware failure, memory corruption, or fatal software bug.
When the Linux kernel encounters an unrecoverable error, it triggers a panic—a controlled shutdown that prevents further damage to the system and filesystem. The kernel stops all processes and displays diagnostic information, often including a stack trace showing where the failure occurred.
Common causes include hardware failures (bad RAM, CPU errors), driver bugs, kernel bugs, or incompatible kernel modules. You'll typically see a message like Kernel panic - not syncing: Fatal exception in interrupt followed by a CPU backtrace.
The system may automatically reboot after a panic (configurable via /proc/sys/kernel/panic), or it may hang waiting for manual intervention. Analyzing panic logs in /var/log/kern.log helps identify the root cause.