On Wed, Feb 22, 2012 at 6:29 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 02/22/2012 04:08 PM, Kees Cook wrote: >>> >>> Hrm, it might be possible to do_exit(SIGSYS) which would be both. It >>> looks like tsk->exit_code would be SIGSYS then, but I'll look a little >>> more closely to see what that'll actually do. >> >> As long as there's no way it can get blocked, I'd be fine with that. >> It would, actually, be better than SIGKILL because, as Andy said, it's >> more distinguishable from other situations. I've long wanted a signal >> to be used for "violated policy" that wasn't just a straight SIGKILL. >> > > Can we really introduce force-kill semantics for a POSIX-defined signal? > Other user space programs might use it for other purposes. > > I'm wondering if the right thing may be to introduce some variant of > exit() which can return more information about a signal, including some > kind of cause code for SIGKILL? While it'd be harder to send back extra info, passing SIGSYS to do_exit() should result in the si_status for the emitted SIGCHLD to be SIGSYS (si_status = (tsk->exit_code & 0x7f)). I think it'll still have a si_code of CLD_KILLED, but it'd be enough for a parent to differentiate the task-death path. I'll try it out before I post another patch rev. A variant that allowed extended exit information would be useful (especially for this patch series), I'm not sure I'd know where to start. cheers! will -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
