Thank you all for your replies, > yes, "borrow" in the sense that: kernel thread DOES NOT have any process > context, and so it can be executed in any process context, and which ever > process context it is executing, when u print the CR3 value, it will belong > to that process which the kernel thread is currently executing under. I've read on LKD by Robert Love book the following: "Because kernel threads do not have any pages in user-space, they do not really deserve their own memory descriptor and page tables. Despite this, kernel threads need some of the data, such as the page tables, even to access kernel memory. To provide kernel threads the needed data, kernel threads use the memory descriptor of whatever task ran previously" I can't really tell which are the data which are needed by kernel threads that the book is talking about..By combining the above with the following (from the same book): "The kernel thread can then use the previous process's page tables as needed. Because kernel threads do not access user-space memory, they make use of only the information in the address space pertaining to kernel memory, which is the same for all processes." I conclude the following: A kernel thread uses only the address space of the previously scheduled user process pertaining to kernel memory for accessing kernel memory. Also, a kernel thread is using the virtual memory mechanism of user process to access kernel memory. That is, it runs on user-space but accesses *only* kernel memory, right? - i.e. it is basically a user process that access only Kernel memory - Why kernel threads cannot directly access kernel memory and use a mechanism used in user-space for accessing it? Sorry for the many questions, any help will be greatly appreciated guys. P.S. Please correct me if I interpreted something wrong. Regards, John K. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
