From: Mike Kravetz <mike.kravetz@oracle.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
"Longpeng (Mike)" <longpeng2@huawei.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, arei.gonglei@huawei.com,
weidong.huang@huawei.com, weifuqiang@huawei.com,
kvm@vger.kernel.org
Subject: Re: [PATCH] mm/hugetlb: avoid get wrong ptep caused by race
Date: Tue, 18 Feb 2020 16:51:53 -0800 [thread overview]
Message-ID: <455abe66-d801-89c4-3e3c-503842fe403a@oracle.com> (raw)
In-Reply-To: <20200218203717.GE28156@linux.intel.com>
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
next prev parent reply other threads:[~2020-02-19 0:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 12:10 [PATCH] mm/hugetlb: avoid get wrong ptep caused by race Longpeng(Mike)
2020-02-18 20:37 ` Sean Christopherson
2020-02-19 0:51 ` Mike Kravetz [this message]
2020-02-19 1:39 ` Longpeng (Mike)
2020-02-19 1:58 ` Sean Christopherson
2020-02-19 12:21 ` Longpeng (Mike)
2020-02-19 16:22 ` Sean Christopherson
2020-02-20 2:32 ` Longpeng (Mike)
2020-02-19 19:33 ` Mike Kravetz
2020-02-20 2:30 ` Longpeng (Mike)
2020-02-21 0:22 ` Mike Kravetz
2020-02-22 2:15 ` Longpeng (Mike)
2020-02-18 20:52 ` Matthew Wilcox
2020-02-19 2:09 ` Longpeng (Mike)
2020-02-19 3:49 ` Mike Kravetz
2020-02-19 12:52 ` Longpeng (Mike)
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