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I know that we can call user space from Kernel Module, using the call_usermodehelper function.

Prototype call_usermodehelper (const char * path, char ** argv, char ** envp, int wait)

Where

const char * path is a path to usermode executable

char ** argv is arg vector for process

char ** envp environment for process

int wait is some sort of enumeration

When I try to run my python script, in this way

    #include <linux/module.h>
    #include <linux/kernel.h>
    #include <linux/fs.h>
    #include <linux/uaccess.h>
    #include <linux/kmod.h>

MODULE_LICENSE("GPL");
static int __init mpc_init(void) {


char *argv[]= {"/bin/bash","-c","/dir1/dir2/file.py",NULL};
static char *envp[]={
    "SHELL=/bin/bash",
    "HOME=/home/pi",
    "TERM=xterm", 
               "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/    local/games:/usr/games",NULL};

printk(KERN_INFO "yes");

return call_usermodehelper(argv[0],argv,envp,UMH_WAIT_EXEC); 

}

static void __exit mpc_exit(void) {       
    printk(KERN_INFO "no");
}

module_init(mpc_init);
module_exit(mpc_exit);

I can see that a process can be created, but It gets killed in short time.

Maybe my module needs allocated memory?

closed as off-topic by Rui F Ribeiro, Jeff Schaller May 27 at 20:02

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  • Try running /bin/bash -c /dir1/dir2/file.py directly from the command line, and you will see why it fails. You are apparently trying to run python code as a bash script. – Johan Myréen May 27 at 19:02
  • It work from command line. Maybe, the reason is that my python file use a lot of modules, and I need to load them with a kernel module? – Michele Lo Presti May 28 at 17:17
  • What do you need bash for? Why don't you start the Python script directly? – Johan Myréen May 28 at 17:57
  • I also ran it directly from command line, but with the same result – Michele Lo Presti May 28 at 19:28