Pass a string parameter with space character to kernel module

When you run insmod ./params.ko mystring="Hello World" your quotes are eaten by the shell and the insmod binary has the string mystring=Hello World as the parameter. It passes it to the kernel as is, and then it all goes down to the kernel parse_args function (in kernel/params.c), which, in turn, calls next_arg to split the next parameter into name and value.

It definitely can handle spaces, as we see the following comment in the code:

/* You can use " around spaces, but can't escape ". *//* Hyphens and underscores equivalent in parameter names. */

and the following conditional statement:

static char *next_arg(char *args, char **param, char **val){    ...    for (i = 0; args[i]; i++) {        if (isspace(args[i]) && !in_quote)            break;    ...}

So the idea is that you need to pass the quotes to the kernel, not to the shell.Don't have a linux box to check the kernel module insertion right now, but I guess the following command will work:

# insmod ./params.ko mystring='"Hello World"'

Here the shell will consume the single quotes, and the parameter for insmod binary will be mystring="Hello World" so these quotes will be passed to kernel as is, which will make it possible to parse the value as you expect. Try that, should work.