> How do you end up with Device nGnRnE in user space? I thought we should > have got some guard page. I guess it is a device file that is mmaped in the user space and later remapped in the kernel using pgprot_noncached(). I can't find the code that inserts a guard page in between vma's can you please help me find that code?
> do_strncpy_from_user() relies on unsafe_get_user() not being able to > read 8 bytes. The problem now is that it doesn't get a page fault but an > alignment one is isn't handled. Yes. > Why addr >= TASK_SIZE? addr here should be the fault address, not pc. You're right. I should have used user_mode(regs). > The simplest would be to use do_bad_area() here without any additional > function. Yes, I should've probably used do_bad_area(). I just wanted to do the minimal stuff.
