Messages in this thread |  | | Date | Thu, 17 Aug 2017 15:09:42 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH-resend] mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages |
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On Wed, 16 Aug 2017 10:18:03 -0700 "Luck, Tony" <tony.luck@intel.com> wrote:
> Speculative processor accesses may reference any memory that has a > valid page table entry. While a speculative access won't generate > a machine check, it will log the error in a machine check bank. That > could cause escalation of a subsequent error since the overflow bit > will be then set in the machine check bank status register. > > Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual > address of the page we want to map out otherwise we may trigger the > very problem we are trying to avoid. We use a non-canonical address > that passes through the usual Linux table walking code to get to the > same "pte". > > Thanks to Dave Hansen for reviewing several iterations of this.
It's unclear (to lil ole me) what the end-user-visible effects of this are.
Could we please have a description of that? So a) people can understand your decision to cc:stable and b) people whose kernels are misbehaving can use your description to decide whether your patch might fix the issue their users are reporting.
Thanks.
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