From: Andrew Morton <akpm@linux-foundation.org>
To: Jane Chu <jane.chu@oracle.com>
Cc: dave@stgolabs.net, jack@suse.cz, linux-nvdimm@lists.01.org,
Hugh Dickins <hughd@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
jglisse@redhat.com, mhocko@suse.com, mike.kravetz@oracle.com
Subject: Re: [PATCH] ipc/shm.c add ->pagesize function to shm_vm_ops
Date: Fri, 27 Jul 2018 14:50:09 -0700 [thread overview]
Message-ID: <20180727145009.5dde68fb680ec148a7504f37@linux-foundation.org> (raw)
In-Reply-To: <20180727211727.5020-1-jane.chu@oracle.com>
On Fri, 27 Jul 2018 15:17:27 -0600 Jane Chu <jane.chu@oracle.com> wrote:
> Commit 05ea88608d4e13 (mm, hugetlbfs: introduce ->pagesize() to
> vm_operations_struct) adds a new ->pagesize() function to
> hugetlb_vm_ops, intended to cover all hugetlbfs backed files.
That was merged three months ago. Can you suggest why this was only
noticed now?
What workload triggered this? I see no cc:stable, but 4.17 is affected?
> With System V shared memory model, if "huge page" is specified,
> the "shared memory" is backed by hugetlbfs files, but the mappings
> initiated via shmget/shmat have their original vm_ops overwritten
> with shm_vm_ops, so we need to add a ->pagesize function to shm_vm_ops.
> Otherwise, vma_kernel_pagesize() returns PAGE_SIZE given a hugetlbfs
> backed vma, result in below BUG:
>
> fs/hugetlbfs/inode.c
> 443 if (unlikely(page_mapped(page))) {
> 444 BUG_ON(truncate_op);
OK, help me out here. How does an incorrect return value from
vma_kernel_pagesize() result in remove_inode_hugepages() deciding that
it's truncating a mapped page?
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next prev parent reply other threads:[~2018-07-27 21:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-27 21:17 [PATCH] ipc/shm.c add ->pagesize function to shm_vm_ops Jane Chu
2018-07-27 21:43 ` Mike Kravetz
2018-07-27 21:50 ` Andrew Morton [this message]
2018-07-28 0:40 ` Jane Chu
2018-07-28 19:02 ` Matthew Wilcox
2018-07-31 3:06 ` Jane Chu
2018-07-30 8:58 ` Michal Hocko
2018-07-31 3:07 ` Jane Chu
2018-07-30 16:44 ` Davidlohr Bueso
2018-07-31 3:08 ` Jane Chu
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