On Mon, Feb 3, 2014 at 12:23 PM, Steve Grubb <sgr...@redhat.com> wrote: > On Monday, February 03, 2014 09:53:23 AM Andy Lutomirski wrote: >> This toggles TIF_SYSCALL_AUDIT as needed when rules change instead of >> leaving it set whenever rules might be set in the future. This reduces >> syscall latency from >60ns to closer to 40ns on my laptop. > > Does this mean that we have processes that don't have the TIF_SYSCALL_AUDIT > flag set? When rules get loaded, how do we get the flag put back into all > processes?
By looping over all processes and setting the flag, which is what my patch does. > > The theory of ops is supposed to be that for anyone not needing audit, there > is only the cost of "if (tif & TIF_SYSCALL_AUDIT)". On current kernels *all* processes have TIF_SYSCALL_AUDIT, even if they don't need auditing because there's nothing to audit. So everything pays the full cost. > That should be it. If you > have audit enabled or had it enabled (which means it might be loaded with new > rules), we want to inspect the syscall. > My point is that there's nothing to inspect -- there are no rules. Unless the audit code needs to do something just in case a non-syscall audit event gets written, in which case the audit code should IMO be fixed. (This is what Eric is talking about, I think.) --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
