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From: Qian Cai <cai@lca.pw>
To: "Longpeng (Mike)" <longpeng2@huawei.com>
Cc: akpm@linux-foundation.org, mike.kravetz@oracle.com,
	kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org,
	arei.gonglei@huawei.com, weidong.huang@huawei.com,
	weifuqiang@huawei.com, kvm@vger.kernel.org, linux-mm@kvack.org,
	Matthew Wilcox <willy@infradead.org>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH v2] mm/hugetlb: fix a addressing exception caused by huge_pte_offset()
Date: Sat, 22 Feb 2020 06:50:42 -0500	[thread overview]
Message-ID: <D70C23C6-75CB-4A68-8E7C-23FE8A0CCA68@lca.pw> (raw)
In-Reply-To: <f274b368-6fdb-2ae3-160e-fd8b105b9ac4@huawei.com>



> On Feb 22, 2020, at 1:33 AM, Longpeng (Mike) <longpeng2@huawei.com> wrote:
> 
> As explained in the commit messages, it's for safe(e.g. avoid the compilier
> mischief). You can also find the same usage in the ARM64's huge_pte_offset() in
> arch/arm64/mm/hugetlbpage.c

Rather than blindly copy over there, are those correct here? What kind of bad compiler optimizations exactly do they try to prevent? Until we understand those details, blindly adding READ_ONCE() will only hide other problems.

  reply	other threads:[~2020-02-22 11:50 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-22  5:23 [PATCH v2] mm/hugetlb: fix a addressing exception caused by huge_pte_offset() Qian Cai
2020-02-22  6:33 ` Longpeng (Mike)
2020-02-22 11:50   ` Qian Cai [this message]
2020-02-22 17:02   ` Matthew Wilcox
2020-02-23  1:24     ` Longpeng (Mike)
2020-02-27 21:41       ` Mike Kravetz
2020-03-21 22:46         ` Andrew Morton
  -- strict thread matches above, loose matches on Subject: below --
2020-02-22  3:33 Longpeng(Mike)
2020-03-21 23:38 ` Mike Kravetz
2020-03-23  2:03   ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2020-03-23  2:54     ` Mike Kravetz
2020-03-23  3:43       ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2020-03-23 14:40       ` Sean Christopherson
2020-03-23 16:44         ` Jason Gunthorpe
2020-03-23 16:09   ` Jason Gunthorpe
2020-03-23 17:27     ` Mike Kravetz
2020-03-23 18:07       ` Jason Gunthorpe
2020-03-23 20:35         ` Mike Kravetz
2020-03-23 22:52           ` Jason Gunthorpe
2020-03-24  2:37             ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2020-03-24 11:55               ` Jason Gunthorpe
2020-03-24 15:25                 ` Mike Kravetz
2020-03-24 15:55                   ` Jason Gunthorpe
2020-03-24 16:19                     ` Mike Kravetz
2020-03-24 17:59                       ` Jason Gunthorpe
2020-03-24 19:47                         ` Mike Kravetz

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