the probe function not being called? - linux-kernel

I want to understand why the probe function not being called.
what do I need to study to fix the problem with any USB type to auto-detected after the insertion automatically?
I use key a keyboard, kernel 5.6.3
Here's my code:
#include <linux/module.h> /*included for all kernel modules*/
#include <linux/kernel.h> /*included for KERN_DEBUG*/
#include <linux/init.h> /*included for __init and __exit macros*/
#include <linux/usb.h>
#include <linux/usb/input.h>
#include <linux/hid.h>
#define MY_USB_VENDOR_ID 0x045e
#define MY_USB_PRODUCT_ID 0x0800
static struct usb_device_id my_usb_table[] = {
{ USB_DEVICE(MY_USB_VENDOR_ID, MY_USB_PRODUCT_ID) },
{},
};
MODULE_DEVICE_TABLE(usb, my_usb_table);
static int
my_pdrv_probe(struct usb_interface *pdev, const struct usb_device_id *id) {
pr_err("Hello\n");
return 0;
}
static void my_pdrv_remove(struct usb_interface *pdev) {
pr_err("Bye\n");
}
static struct usb_driver mypdrv = {
.name = "my first usb driver",
.probe = my_pdrv_probe,
.disconnect = my_pdrv_remove,
};
// module_usb_driver(mypdrv);
static int __init my_pdev_init(void)
{
pr_err("Hello Guy\n");
/* Refister with kernel */
usb_register(&mypdrv);
return 0;
}
static void __exit my_pdev_remove(void)
{
pr_err("Bye Guy\n");
/* Unregister from kernel */
usb_deregister(&mypdrv);
}
module_init(my_pdev_init);
module_exit(my_pdev_remove);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sohaib Mohammed");
MODULE_DESCRIPTION("first usb driver module");
MODULE_VERSION("0.1");

Related

Sound cards don't show up in /proc/asound/cards

I've this driver:
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <sound/pcm.h>
#include <sound/soc.h>
#include <sound/soc-dai.h>
#include <sound/soc-dapm.h>
static const struct snd_soc_dapm_route max9880_dapm_routes[] = {
{"Mono out", NULL, "Mono Mixer"}
};
static struct snd_soc_codec_driver soc_codec_dev_max9880 = {
.component_driver = {
.dapm_routes = max9880_dapm_routes,
.num_dapm_routes = ARRAY_SIZE(max9880_dapm_routes)
}
};
static struct snd_soc_dai_driver max9880_dai = {
.name = "max9880",
.playback = {
.stream_name = "Playback",
.channels_min = 1,
.channels_max = 1
}
};
static int max9880_platform_probe(struct platform_device *pdev)
{
int ret;
snd_printk(KERN_ALERT "1. platform probe");
ret = snd_soc_register_codec(&pdev->dev, &soc_codec_dev_max9880,
&max9880_dai, 1);
return ret;
}
static int max9880_platform_remove(struct platform_device *pdev)
{
snd_printk(KERN_ALERT "2. platform remove");
snd_soc_unregister_codec(&pdev->dev);
return 0;
}
static const struct of_device_id max9880_device_id[] = {
{ .compatible = "max9880" },
{}
};
MODULE_DEVICE_TABLE(of, max9880_device_id);
static struct platform_driver max9880_platform_driver = {
.driver = {
.name = "max9880",
.of_match_table = of_match_ptr(max9880_device_id),
},
.probe = &max9880_platform_probe,
.remove = &max9880_platform_remove,
};
module_platform_driver(max9880_platform_driver);
and I use insmod to load the module into the kernel. This all seems to work well, and I'm also able to do a rmmod without any problem. However I don't get any entries in /proc/asound/cards meaning that my module isn't recoqnized as a sound card. What am I missing?

Shared Memory between Kernel and User

I am currently working on a kernel module for a RaspberryPi 3 and am new to this area. This should generate an interrupt on a rising or falling edge. In the corresponding ISR, a time stamp is set and a signal is generated to notify a user application.
I have taken the signaling for the sake of the code.
My goal is now to write the value of the time stamp into a shared memory and the user application can read it out after an incoming signal in order to measure the latency between the interrupt and the signal received in the user application. I have already researched but found no solution. How do I map the virtual kernel address of the allocated memory into the user application and what steps are necessary?
Thanks in advance.
Kernel Code:
/****************************************************************************/
/* Kernelmodul Shared Memory */
/****************************************************************************/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
// kmalloc
#include <linux/slab.h>
// ioremap
#include <asm/io.h>
/****************************************************************************/
/* Define block */
/****************************************************************************/
#define DriverAuthor ""
#define DriverDescription "Shared Memory"
#define InterruptPin 26
#define GPIO_PIN_DEV_STR "PIN"
#define GPIO_PIN_STR "Timestamp"
unsigned int * timerAddr;
unsigned int time = 0;
unsigned int * SHMvirtual = 0;
/****************************************************************************/
/* Module params declaration block */
/****************************************************************************/
static short int gpio_pin = InterruptPin;
/****************************************************************************/
/* Interrupts variables block */
/****************************************************************************/
short int irq_gpio_pin = InterruptPin;
short int irq_enabled = 0; // this is only a flag
/****************************************************************************/
/* IRQ handler */
/****************************************************************************/
static irqreturn_t ISR(int irq, void *dev_id, struct pt_regs *regs) {
unsigned long flags;
// disable hard interrupts (remember them in flag 'flags')
local_irq_save(flags);
time = timerAddr[1];
*SHMvirtual = time;
// restore hard interrupts
local_irq_restore(flags);
return IRQ_HANDLED;
}
/****************************************************************************/
/* This function configures interrupts. */
/****************************************************************************/
void configInterrupts(void) {
if (gpio_request(gpio_pin, GPIO_PIN_STR))
{
printk(KERN_INFO "GPIO request faiure %d\n", gpio_pin);
return;
}
if ( (irq_gpio_pin = gpio_to_irq(gpio_pin)) < 0 )
{
printk(KERN_INFO "GPIO to IRQ mapping faiure %d\n", gpio_pin);
return;
}
printk(KERN_INFO "Mapped int %d\n", irq_gpio_pin);
if (request_irq(irq_gpio_pin, (irq_handler_t ) ISR, (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING), GPIO_PIN_STR,
GPIO_PIN_DEV_STR))
{
printk("Interrupt Request failure\n");
return;
}
return;
}
/****************************************************************************/
/* This function releases interrupts. */
/****************************************************************************/
void releaseInterrupt(void) {
free_irq(irq_gpio_pin, GPIO_PIN_DEV_STR);
gpio_free(gpio_pin);
return;
}
/****************************************************************************/
/* Module init / cleanup block. */
/****************************************************************************/
int initModule(void) {
printk(KERN_INFO "Hello\n");
configInterrupts();
timerAddr = ioremap(0x3F003000, 0x20);
SHMvirtual = (unsigned int *)kmalloc(sizeof(time),GFP_USER);
return 0;
}
void cleanupModule(void) {
printk(KERN_INFO "Goodbye\n");
releaseInterrupt();
kfree(SHMvirtual);
return;
}
module_init(initModule);
module_exit(cleanupModule);
/****************************************************************************/
/* Module licensing/description block. */
/****************************************************************************/
MODULE_LICENSE("GPL");
MODULE_AUTHOR(DriverAuthor);
MODULE_DESCRIPTION(DriverDescription);

Kernel call_usermodehelper fail to open GUI application

I use call_usermodehelper to open qt why I can't open? How to solve this problem? Or other way use kernel to open user-space application?
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kmod.h>
MODULE_LICENSE("GPL");
static int umh_test( void ) {
char *argv[] = { "/usr/bin/qtcreator", NULL };
static char *envp[] = {
"HOME=/",
"TERM=linux",
"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
NULL
};
return call_usermodehelper( argv[0], argv, envp, UMH_WAIT_PROC);
}
static int hello_init(void)
{
int ret = 0;
ret = umh_test();
printk(KERN_INFO "retval11: %d\n", ret);
return 0;
}
static void hello_exit(void)
{
printk(KERN_INFO "BYE\n");
}
module_init(hello_init);
module_exit(hello_exit);
Picture showing the error picture:

Network hooks hanging the system

I was testing the network hook code given in https://en.wikipedia.org/wiki/Hooking . My kernel version is 3.11.
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <net/ip.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/in.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
/* Port we want to drop packets on */
static const uint16_t port = 25;
/* This is the hook function itself */
static unsigned int hook_func(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *)){
struct iphdr *iph = ip_hdr(*pskb);
struct tcphdr *tcph, tcpbuf;
if (iph->protocol != IPPROTO_TCP)
return NF_ACCEPT;
tcph = skb_header_pointer(*pskb, ip_hdrlen(*pskb), sizeof(*tcph), &tcpbuf);
if (tcph == NULL)
return NF_ACCEPT;
return (tcph->dest == port) ? NF_DROP : NF_ACCEPT;
}
/* Used to register our hook function */
static struct nf_hook_ops nfho = {
.hook = hook_func,
.hooknum = NF_INET_PRE_ROUTING,
.pf = NFPROTO_IPV4,
.priority = NF_IP_PRI_FIRST,
};
static __init int my_init(void)
{
return nf_register_hook(&nfho);
}
static __exit void my_exit(void)
{
nf_unregister_hook(&nfho);
}
module_init(my_init);
module_exit(my_exit);
But after loading , the above code is freezing the system. Can anybody please tell, what is the reason for that?. I think that the above code might have already tested in some lower versions of kernel. So I doubt, some kernel parameters or features have been changed.

register_kretprobe fails with a return value of -2

I have written a kretprobe to hook on to the randomize_stack_top() function mentioned in fs/binfmt_elf.c file. On loading the LKM with insmod the register_kretprobe() call fails with a return value of -2. How do I go about debugging/rectifying that in order to get my module started ?
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <asm/uaccess.h>
#include <asm/current.h>
#include <asm/param.h>
/* Global variables */
int randomize_stack_retval;
// randomize_stack_top() kretprobe specific declarations
static char stack_name[NAME_MAX] = "randomize_stack_top";
static int randomize_stack_top_entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
return 0;
}
static int randomize_stack_top_ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
randomize_stack_retval = regs_return_value(regs); //store in global variable
printk(KERN_INFO "%d\n",randomize_stack_retval);
return 0;
}
//randomize_stack_top return probe
static struct kretprobe randomize_kretprobe = {
.handler = randomize_stack_top_ret_handler,
.entry_handler = randomize_stack_top_entry_handler,
.maxactive = NR_CPUS,
};
/* Register kretprobe */
static int __init kretprobe_init(void)
{
int ret;
randomize_kretprobe.kp.symbol_name = stack_name;
ret = register_kretprobe(&randomize_kretprobe);
if (ret < 0) {
printk(KERN_INFO "register_kretprobe failed, returned %d\n",
ret);
return -1;
}
printk(KERN_INFO "Planted return probe at %s: %p\n",
randomize_kretprobe.kp.symbol_name, randomize_kretprobe.kp.addr);
return 0;
}
/* Unregister kretprobe */
static void __exit kretprobe_exit(void)
{
unregister_kretprobe(&randomize_kretprobe);
printk(KERN_INFO "kretprobe at %p unregistered\n",
randomize_kretprobe.kp.addr);
// nmissed > 0 suggests that maxactive was set too low.
printk(KERN_INFO "Missed probing %d instances of %s\n",
randomize_kretprobe.nmissed, randomize_kretprobe.kp.symbol_name);
}
module_init(kretprobe_init);
module_exit(kretprobe_exit);
MODULE_LICENSE("GPL");
-2 corresponds to -ENOENT (you can check that in include/uapi/asm-generic/errno-base.h). Probably, it means that kprobe cannot find symbol with given name.
Note, that randomize_stack_top is static function with a short implementation and it is used only once. So it can be inlined by the gcc.

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