https://bugzilla.kernel.org/show_bug.cgi?id=70801 Bug ID: 70801 Summary: ptrace PEEKDATA API is incorrect Product: Documentation Version: unspecified Hardware: All OS: Linux Status: NEW Severity: normal Priority: P1 Component: man-pages Assignee: documentation_man-pages@xxxxxxxxxxxxxxxxxxxx Reporter: ahh@xxxxxxxxxx Regression: No ptrace(2) manual gives us the API: PTRACE_PEEKTEXT, PTRACE_PEEKDATA Read a word at the address addr in the tracee's memory, returning the word as the result of the ptrace() call. Linux does not have separate text and data address spaces, so these two requests are currently equivalent. (data is ignored.) checking kernel/ptrace.c gives us: int ptrace_request(struct task_struct *child, long request, unsigned long addr, unsigned long data) { ... switch (request) { case PTRACE_PEEKTEXT: case PTRACE_PEEKDATA: return generic_ptrace_peekdata(child, addr, data); int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, unsigned long data) { unsigned long tmp; int copied; copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); if (copied != sizeof(tmp)) return -EIO; return put_user(tmp, (unsigned long __user *)data); } So clearly data is _not_ ignored and the word is _not_ returned as the result of ptrace. I also verified that various working ptrace calls in fact use the API as the kernel has it, not the man page. This wants a relatively simple fix itself, but it does _not_ fill me with confidence as to the accuracy of the man page for the other requests; I strongly suggest you audit them for accuracy (sadly I don't have time to do this myself.) Just a thought. -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
