Roland McGrath <[EMAIL PROTECTED]> wrote: > That old ptrace check seems pretty questionable to me. I think what you > want is for the nommu world's get_user_pages/access_process_vm when called > with force=1,write=1 on a read-only MAP_PRIVATE page to do something more > morally similar to the mmu world's COW than it does now.
Such as what? You *can't* do COW without relocating all the pointers userspace may have into that VMA. However, unless you force non-sharing of R/O MAP_PRIVATE VMAs, you will have text segments of executables and libraries shared with other processes. Imagine: you set a breakpoint in uclibc read() and your whole system dies instantly. What I did is to say that if a process has PT_TRACED set then the MAP_PRIVATE VMAs start with their own copies. The debugger can set this in a new process by cloning it with appropriate CLONE_xxx flags. It's not perfect, I know, but it's the best I could come up with as a solution to debugging things in a NOMMU environment that supports shared libraries and executables. David - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
