On Wed, Nov 12, 2014 at 4:31 PM, Luck, Tony <tony.l...@intel.com> wrote: >> v2's not going to make a difference unless you're using uprobes at the >> same time. > > Not (knowingly) using uprobes. System is installed with a RHEL7 userspace ... > but is essentially > idle except for my test program. > >> In the interest of my sanity, can you add something like >> BUG_ON(!user_mode_vm(regs)) or the mce_panic equivalent before calling >> memory_failure? > > I don't think that can possibly trip - we can only end up with a recoverable > error from > a user mode access. But I'll see about adding it anyway > >> What happens if there's a shared bank but the actual offender has a >> higher order than the cpu that finds the error? > > This test case injects a memory error which is logged in bank1. This bank is > shared by the > two hyperthreads that are on the same core. The mce_severity() function > distinguishes > which is the active thread and which the innocent bystander by looking at > MCG_STATUS. > In the active thread MCG_STATUS.EIPV is 1, in the bystander it is 0. The > returned severity > is MCE_AR_SEVERITY for the thread that hit the error, MCE_KEEP_SEVERITY for > the bystander. > So it doesn't matter which thread has the lower order and sees it first. > >> Is this something I can try under KVM? > > I don't know if KVM has a way to simulate a machine check event.
With mce-inject and this input: CPU 1 BANK 0 STATUS uc s ar val en 0x0134 MCGSTATUS mcip eipv ADDR 4096 MISC 0 IN_PROC EXCP I blow up because mce-inject doesn't have a credible emulation of process context (i.e. IN_PROC doesn't work). --Andy > > -Tony -- 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/
