On Fri, Feb 28, 2014 at 07:13:06AM -0800, H. Peter Anvin wrote: > If I'm reading this right we end up going from the page fault > tracepoint to copy_from_user_nmi() without going through NMI, and the > cr2 corruption is obvious. I guess the assumption that only the NMI > path needed to save cr2 is flawed?
It was never assumed it would only go through NMI, but that it would be NMI safe -- and as it turns out, it is that. What I did assume was that any other callsites would be safe, seeing how they'd already be running in 'normal' contexts. I had not considered people putting tracepoints _that_ early in the exception paths. Note that there's more tracepoints there than the one mentioned. -- 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/
