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Can you elaborate? If I strace a process which makes a ptrace system call that is just another userland process and my userland process has a page table entry j
by bogomipz 9y ago
Can you elaborate? If I strace a process which makes a ptrace system call that is just another userland process and my userland process has a page table entry just like any other userland process.
- tedunangst 9y agoYou call ptrace and ask to read another process's memory. The kernel has to turn the requested VA in that address space into a physical page (walking those page tables, not yours) then copy the memory (from some VA in kernel space). This is quicker if you can turn a PA into a VA by simply adding an offset.
- bogomipz 9y agoI see. I misinterpreted your previous comment. Cheers.