On 07.06.22 23:59, Andrew Morton wrote: > On Tue, 7 Jun 2022 14:36:00 +0200 David Hildenbrand <david@xxxxxxxxxx> 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, 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? For example, I'm not even sure if we're allowed to use virt_to_kpte() out of random context at all. If we have a PMD direct map, why should it be okay to use virt_to_kpte()? Maybe I am just wrong, I asked that question on the next patch version as well. -- Thanks, David / dhildenb
