On Thursday 26 January 2012 01:59, Jamie Lokier wrote: > Denys Vlasenko wrote: > > (2) syscall exit compat-ness is known from entry type - no need to indicate it; and > > (3) if we would flag syscall entry with an event value in wait status, then syscall > > exit will be already distinquisable. > > > > Thus, minimally we need one new option, PTRACE_O_TRACE_SYSENTRY - > > "on syscall entry ptrace stop, set a nonzero event value in wait status" > > , and two event values: PTRACE_EVENT_SYSCALL_ENTRY (for native entry), > > PTRACE_EVENT_SYSCALL_ENTRY1 for compat one. > > PTRACE_EVENT_SYSCALL_EXIT would cleanly indicate that the new option > is actually working without the tracer needing to do a fork+test, if > PTRACE_ATTACH is used and for some reason the tracer sees a syscall > exit first. Can't happen. After PTRACE_ATTACH, you can only see tracee dying, or getting a signal delivery (usually a SIGSTOP). Anything else would be a kernel bug. -- vda -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
