linux中具有相同虚拟和物理地址空间的两个进程（共享大页面）

Question

I am aware of the shared memory creation(with normal pages), where the virtual addresses of the process which creates and the virtual address of process which attaches to it are different. But they internally will be mapped to the same physical address frame.

In our project we allocate huge pages(contiguous and unswappad memory) and we use third party API's(intel DPDK) for creating/attaching shared memory(from huge pages). I have observed virtual address for accessing the huge pages is same in all the processes.

is it possible?I am curious to know how is that possible?

Answer 1

if you just want to know that same virtual address from two processes can be mapped to same physical page then answer is yes. There is nothing wrong in this situation. But if on creating shared pages, you always get same addresses for all processes who are sharing the physical page, it is unique but as you said you are using some API then it is related with that API functionality(your how part of question). If you are dead sure that this is the case then in my view it is a vulnerability which can be exploited. you should consult with relevant authorities/experts to convey your findings.

Answer 2

The two proccesses have the same virtual address!It's right !After mapping virtual address and physical address, master process writes the mapping information to a file; Slave process read the file and do the same mapping !