Messages in this thread | | | Subject | Re: [PATCH] mm/hugetlb: avoid get wrong ptep caused by race | From | Mike Kravetz <> | Date | Tue, 18 Feb 2020 16:51:53 -0800 |
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On 2/18/20 12:37 PM, Sean Christopherson wrote: > On Tue, Feb 18, 2020 at 08:10:25PM +0800, Longpeng(Mike) wrote: >> Our machine encountered a panic after run for a long time and >> the calltrace is: > > What's the actual panic? Is it a BUG() in hugetlb_fault(), a bad pointer > dereference, etc...?
I too would like some more information on the panic. If your analysis is correct, then I would expect the 'ptep' returned by huge_pte_offset() to not point to a pte but rather some random address. This is because the 'pmd' calculated by pmd_offset(pud, addr) is not really the address of a pmd. So, perhaps there is an addressing exception at huge_ptep_get() near the beginning of hugetlb_fault()?
ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); if (ptep) { entry = huge_ptep_get(ptep); ...
-- Mike Kravetz
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