From: Dan Williams <dan.j.williams@intel.com>
To: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@linux.intel.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
mauricio.porto@hpe.com, Linux MM <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: Fix mmap MAP_POPULATE for DAX pmd mapping
Date: Mon, 30 Nov 2015 14:08:53 -0800 [thread overview]
Message-ID: <CAPcyv4gY2SZZwiv9DtjRk4js3gS=vf4YLJvmsMJ196aps4ZHcQ@mail.gmail.com> (raw)
In-Reply-To: <1448309082-20851-1-git-send-email-toshi.kani@hpe.com>
On Mon, Nov 23, 2015 at 12:04 PM, Toshi Kani <toshi.kani@hpe.com> wrote:
> The following oops was observed when mmap() with MAP_POPULATE
> pre-faulted pmd mappings of a DAX file. follow_trans_huge_pmd()
> expects that a target address has a struct page.
>
> BUG: unable to handle kernel paging request at ffffea0012220000
> follow_trans_huge_pmd+0xba/0x390
> follow_page_mask+0x33d/0x420
> __get_user_pages+0xdc/0x800
> populate_vma_page_range+0xb5/0xe0
> __mm_populate+0xc5/0x150
> vm_mmap_pgoff+0xd5/0xe0
> SyS_mmap_pgoff+0x1c1/0x290
> SyS_mmap+0x1b/0x30
>
> Fix it by making the PMD pre-fault handling consistent with PTE.
> After pre-faulted in faultin_page(), follow_page_mask() calls
> follow_trans_huge_pmd(), which is changed to call follow_pfn_pmd()
> for VM_PFNMAP or VM_MIXEDMAP. follow_pfn_pmd() handles FOLL_TOUCH
> and returns with -EEXIST.
>
> Reported-by: Mauricio Porto <mauricio.porto@hpe.com>
> Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Matthew Wilcox <willy@linux.intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> ---
Hey Toshi,
I ended up fixing this differently with follow_pmd_devmap() introduced
in this series:
https://lists.01.org/pipermail/linux-nvdimm/2015-November/003033.html
Does the latest libnvdimm-pending branch [1] pass your test case?
[1]: git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm libnvdimm-pending
next prev parent reply other threads:[~2015-11-30 22:08 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-23 20:04 [PATCH] mm: Fix mmap MAP_POPULATE for DAX pmd mapping Toshi Kani
2015-11-23 20:53 ` Dan Williams
2015-11-23 22:15 ` Toshi Kani
2015-11-30 22:08 ` Dan Williams [this message]
2015-12-02 2:19 ` Toshi Kani
2015-12-02 3:45 ` Dan Williams
2015-12-02 17:43 ` Toshi Kani
2015-12-02 17:01 ` Dan Williams
2015-12-02 18:06 ` Dan Williams
2015-12-02 19:26 ` Toshi Kani
2015-12-02 19:00 ` Dan Williams
2015-12-02 20:02 ` Toshi Kani
2015-12-02 20:12 ` Toshi Kani
2015-12-02 19:57 ` Dan Williams
2015-12-02 21:37 ` Toshi Kani
2015-12-02 20:54 ` Dan Williams
2015-12-02 21:55 ` Toshi Kani
2015-12-03 23:43 ` Dan Williams
2015-12-04 16:55 ` Toshi Kani
2015-12-02 22:00 ` Dave Hansen
2015-12-02 22:03 ` Dan Williams
2015-12-02 22:09 ` Dave Hansen
2015-12-03 0:21 ` Toshi Kani
2015-12-02 23:33 ` Dan Williams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAPcyv4gY2SZZwiv9DtjRk4js3gS=vf4YLJvmsMJ196aps4ZHcQ@mail.gmail.com' \
--to=dan.j.williams@intel.com \
--cc=akpm@linux-foundation.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nvdimm@ml01.01.org \
--cc=mauricio.porto@hpe.com \
--cc=ross.zwisler@linux.intel.com \
--cc=toshi.kani@hpe.com \
--cc=willy@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).