A kernel Oops and what it signifies
Here are a quick few things to realize regarding a kernel Oops.
First off, an Oops is not the same as a segfault – a segmentation fault... It might, as a side effect, cause a segfault to occur, and thus the process context might receive the fatal SIGSEGV signal. This, of course, has the poor process caught in the crossfire.
Next, an Oops is not the same thing as a full-fledged kernel panic. A panic implies the system is in an unusable state. It might lead up to this, especially on production systems (we cover kernel panic in Chapter 10, Kernel Panic, Lockups and Hangs). Note though, that the kernel provides several sysctl tunables (editable by root, of course) regarding what circumstances can lead to the kernel panicking. We can check them out – on my x86_64 Ubuntu 20.04 guest running our custom production kernel, here they are:
$ cd /proc/sys/kernel/ $ ls panic_on_* panic_on_io_nmi panic_on_oops panic_on_rcu_stall...
