When working with Linux kernel modules, parameters control their behavior at runtime. While /sys/module/<module_name>/parameters/ is the standard interface, some modules don't expose their parameters through sysfs. As a developer, you need reliable methods to inspect these values.

The modinfo command shows parameter information, including default values:

modinfo -p <module_name>
# Example:
modinfo -p e1000

For currently loaded modules, examine /proc/modules:

cat /proc/modules | grep <module_name>

Many modules log their parameters during initialization. Check kernel messages:

dmesg | grep <module_name>

For programmatic access in C:

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>

static int get_module_params(const char *modname)
{
    struct module *mod;
    unsigned int i;
    
    list_for_each_entry(mod, &THIS_MODULE->list, list) {
        if (strcmp(mod->name, modname) == 0) {
            printk(KERN_INFO "Module %s parameters:\n", modname);
            for (i = 0; i < mod->num_kp; i++) {
                struct kernel_param *kp = &mod->kp[i];
                printk(KERN_INFO "%s: %p\n", kp->name, kp->arg);
            }
            return 0;
        }
    }
    return -ENOENT;
}

For advanced debugging with SystemTap:

probe module("<module_name>").function("*") {
    printf("Parameter values at %s:%d\n", probefunc(), probeline())
    /* Add parameter inspection logic here */
}

When parameters aren't exposed through standard interfaces, consider:

• Recompiling the module with debug options
• Using kernel debugging tools like kgdb
• Checking the module's source code for parameter declarations

Remember that accessing module parameters might require root privileges. Always:

• Validate inputs when writing scripts
• Handle cases where modules aren't loaded
• Consider security implications of exposing parameter values

When working with Linux kernel modules, parameters allow runtime configuration without recompiling. While /sys/module/<module_name>/parameters/ is the standard interface, some modules might not expose parameters through this mechanism. Here are alternative approaches to inspect module parameters.

The /proc/modules file contains information about all loaded modules, including their memory addresses:

cat /proc/modules
# Example output:
# nf_conntrack 126976 2 nf_nat,xt_conntrack, Live 0xffffffffc05b8000

The modinfo command shows declared parameters, but not their current values:

modinfo nf_conntrack
# Output includes:
# parm:           hashsize:uint
# parm:           expect_hashsize:uint

For modules without sysfs interface, you might need to examine kernel memory:

# First find module text address
grep nf_conntrack /proc/modules
# Then use gdb to examine symbols (requires kernel debug symbols)
gdb /usr/lib/debug/boot/vmlinux-$(uname -r)
(gdb) p &nf_conntrack_hashsize

SystemTap can probe module parameters at runtime:

probe module("nf_conntrack").function("*") {
    printf("Parameter values might be accessible via: %s\n", pp())
}

Some modules provide custom debugfs entries:

ls /sys/kernel/debug/

Here's how to check TCP keepalive parameters:

cat /proc/sys/net/ipv4/tcp_keepalive_time
cat /proc/sys/net/ipv4/tcp_keepalive_intvl
cat /proc/sys/net/ipv4/tcp_keepalive_probes

Remember that parameter access methods vary by module implementation. When standard interfaces aren't available, you might need to consult the module's source code or documentation for specific inspection methods.