Messages in this thread | | | Date | Wed, 8 Jun 2022 11:06:45 +0800 | Subject | Re: Re: [PATCH] mm/memory-failure: don't allow to unpoison hw corrupted page | From | zhenwei pi <> |
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On 6/8/22 07:43, HORIGUCHI NAOYA(堀口 直也) wrote: > On Tue, Jun 07, 2022 at 02:59:59PM -0700, Andrew Morton wrote: >> On Tue, 7 Jun 2022 14:36:00 +0200 David Hildenbrand <david@redhat.com> wrote: >> >>> On 06.06.22 11:15, HORIGUCHI NAOYA(堀口 直也) wrote: >>>>>> [ 917.864266] <TASK> >>>>>> [ 917.864961] clear_huge_page+0x147/0x270 >>>>>> [ 917.866236] hugetlb_fault+0x440/0xad0 >>>>>> [ 917.867366] handle_mm_fault+0x270/0x290 >>>>>> [ 917.868532] do_user_addr_fault+0x1c3/0x680 >>>>>> [ 917.869768] exc_page_fault+0x6c/0x160 >>>>>> [ 917.870912] ? asm_exc_page_fault+0x8/0x30 >>>>>> [ 917.872082] asm_exc_page_fault+0x1e/0x30 >>>>>> [ 917.873220] RIP: 0033:0x7f2aeb8ba367 >>>>>> >>>>>> I don't think of a workaround for this now ... >>>>>> >>>>> >>>>> Could you please tell me how to reproduce this issue? >>>> >>>> You are familiar with qemu-monitor-command, so the following procedure >>>> should work for you: >>>> >>>> - run a process using hugepages on your VM, >>>> - check the guest physical address of the hugepage (page-types.c is helpful for this), >>>> - inject a MCE with virsh qemu-monitor-command on the guest physical address, then >>>> - unpoison the injected physical address. >>> >>> That's triggered via debugfs / HWPOISON_INJECT, right? >>> >>> That's a DEBUG_KERNEL option, so I'm not 100% sure if we really want to >>> cc stable. > > Sure, the impact of the bug is limited. > >> >> Sure, it's hardly a must-have. But let's also take the patch >> complexity&risk into account. This is one dang simple patch. >> >> Or is it. Should these things be happening outside mf_mutex? What the >> heck is the role of mf_mutex anyway? > > mf_mutex is to ensure that only one error handling thread can handle > the pfn at one time, but set_mce_nospec() is called outside it now. > So if we want to prevent the race with unmap, both of set_mce_nospec() > and the new kpte check might need to be done in mf_mutex. > > - Naoya Horiguchi
OK, I'll sent a v2 patch which includes: - this change gets protected by mf_mutex - use -EOPNOTSUPP instead of -EPERM
By the way, I assume that the similar trace(provided by Naoya) is not a same issue. It seems undissolved huge page with corrupted KPTE. I'm trying to fix it ...
-- zhenwei pi
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