On Tue, Jul 21, 2015 at 7:01 PM, Brian Gerst <brgerst@xxxxxxxxx> wrote: > On Tue, Jul 21, 2015 at 3:59 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote: >> modify_ldt has questionable locking and does not synchronize >> threads. Improve it: redesign the locking and synchronize all >> threads' LDTs using an IPI on all modifications. > > What does this fix? I can see sending an IPI if the LDT is > reallocated, but on every update seems unnecessary. > It prevents nastiness in which you're in user mode with an impossible CS or SS, resulting in potentially interesting artifacts in interrupts, NMIs, etc. > -- > Brian Gerst -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html