On Fri, Apr 10, 2015 at 4:18 PM, Andi Kleen <a...@firstfloor.org> wrote: > On Fri, Apr 10, 2015 at 04:15:39PM -0700, Andy Lutomirski wrote: >> On Fri, Apr 10, 2015 at 4:05 PM, Andi Kleen <a...@firstfloor.org> wrote: >> >> One might argue that this code serves no purpose, but it's there, so >> >> we had better keep our per-invocation usage of DEBUG_STACK within 4k. >> > >> > Only if you run NKLD. I doubt KDB or GDB support nesting. >> > We can ask Jan if he still uses it. >> >> You can trigger these things in various ways with kprobes, >> single-stepping, and user-space watchpoints. These things can >> definitely nest in interesting ways. Whether or not the IST shift >> mechanism is involved if they nest is a complicated question, because >> there's also the "debug" IDT in play. > > Yes we need it for (old style) kprobes in those paths. > > For user space it shouldn't matter.
For entries directly from userspace, we're not using the IST stack any more. --Andy > > -Andi > > -- > a...@linux.intel.com -- Speaking for myself only. -- Andy Lutomirski AMA Capital Management, LLC -- 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/
