On Fri, Jul 24, 2015 at 01:22:11PM -0700, Linus Torvalds wrote: > On Fri, Jul 24, 2015 at 12:55 PM, Peter Zijlstra <pet...@infradead.org> wrote: > > > > I worry that we'll end up running the do_debug() handlers from effective > > NMI context. > > > > The NMI might have preempted locks which these handlers require etc.. > > If #DB takes any locks like that, then #DB is broken. > > Pretty much by definition, a data breakpoint can happen on pretty much > absolutely any code. This is in no way NMI-specific as far as I can > tell. > > Do we really take locks in the #DB handler?
do_debug() send_sigtrap() force_sig_info() spin_lock_irqsave() Now, I don't pretend to understand the condition before send_sigtrap(), so it _might_ be ok, but it sure as heck could do with a comment. -- 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/