* David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote: > On Mon, 2018-02-19 at 10:20 +0100, Peter Zijlstra wrote: > > > > I did not update or otherwise change packages while I was bisecting; the > > machine is: > > > > vendor_id : GenuineIntel > > cpu family : 6 > > model : 62 > > model name : Intel(R) Xeon(R) CPU E5-2680 v2 @ 2.80GHz > > stepping : 4 > > microcode : 0x428 > > That's IVX with a microcode that doesn't *have* IBRS/IBPB. I don't > think there's a publicly available microcode that does; I assume you > didn't have one and build it into your kernel for early loading, and > thus you really weren't even using IBRS here? The code never even gets > patched in? Note that PeterZ's boot troubles only match the *symptoms* of the spurious failures reported by Tim Chen. Your commit wasn't bisected to. I linked these two reports on the (remote) possibility that they might be related via some alignment dependent bug somewhere else in the x86 kernel - possibly completely unrelated to any IBRS/IBPB details. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html