panic

README.md

@@ -39,3 +39,4 @@ See also: <https://superuser.com/questions/351387/how-to-stop-kernel-messages-fr
         1. [debugfs](kernel_module/debugfs.c)
         1. [fops](kernel_module/fops.c)
         1. [workqueue](kernel_module/workqueue.c)
+        1. [panic](kernel_module/panic.c)

kernel_module/hello.c

@@ -11,6 +11,8 @@ Hello world module.
 #include <linux/module.h>
 #include <linux/kernel.h>
 
+MODULE_LICENSE("GPL");
+
 int init_module(void)
 {
 	printk(KERN_INFO "hello init\n");

kernel_module/hello2.c

@@ -7,6 +7,8 @@ Mostly to check that our build infrastructure can handle more than one module!
 #include <linux/module.h>
 #include <linux/kernel.h>
 
+MODULE_LICENSE("GPL");
+
 int init_module(void)
 {
 	printk(KERN_INFO "hello2 init\n");

kernel_module/panic.c

@@ -0,0 +1,26 @@
+/*
+It will happen eventually, so you might as well learn do deal with it.
+
+TODO: how to scroll up to see full trace? Shift + Page Up does not work as it normally does:
+https://superuser.com/questions/848412/scrolling-up-the-failed-screen-with-kernel-panic
+
+The alternative is to get the serial data out streamed to console or to a file:
+
+- https://superuser.com/questions/269228/write-qemu-booting-virtual-machine-output-to-a-file
+- http://www.reactos.org/wiki/QEMU#Redirect_to_a_file
+*/
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+int init_module(void)
+{
+	printk(KERN_INFO "panic init\n");
+	panic("hello panic");
+	return 0;
+}
+
+void cleanup_module(void)
+{
+	printk(KERN_INFO "panic cleanup\n");
+}

kernel_module/workqueue_cheat.c

@@ -1,4 +1,3 @@
-
 /*
 Usage:
 
@@ -7,6 +6,9 @@ Usage:
 	rmmod workqueue
 
 Creates a separate thread. So init_module can return, but some work will still get done.
+
+TODO why can't call this workqueue.ko?
+https://unix.stackexchange.com/questions/364956/how-can-insmod-fail-with-kernel-module-is-already-loaded-even-is-lsmod-does-not
 */
 
 #include <linux/kernel.h>