Hello,

I have been working on a loadable kernel module for a rooted android device which requires me to access mm_struct members.

I was using the following code to access the data in the read function:

struct task_struct* task;
struct mm_struct* test_mm;
int len;

for_each_process{
task_lock(task);
test_mm = task->mm;
len = test_mm->arg_end - test_mm->arg_start;

/* some code*/

task_unlock(task);
}

Compiling and loading does not lead to an error. However, on doing a cat /dev/my_device, the device restarts and I lose root access. I tired this iteratively by accessing just mm->arg_start and a few other mm_struct members but it still led to a restart.

My kernel version is 3.1.10 on running on Jellybean

I was wondering if there are any restrictions on accessing certain sections of the mm_struct for each process.

Since this is my first post in this forum, moderators please let me know if I should post this query someplace else.

Thanks for your help in advance.