linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Li Wang <liwang@redhat.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
	Linux-MM <linux-mm@kvack.org>,  LTP List <ltp@lists.linux.it>,
	xishi.qiuxishi@alibaba-inc.com, mhocko@kernel.org,
	 Cyril Hrubis <chrubis@suse.cz>
Subject: Re: [MM Bug?] mmap() triggers SIGBUS while doing the​ ​numa_move_pages() for offlined hugepage in background
Date: Fri, 2 Aug 2019 17:59:09 +0800	[thread overview]
Message-ID: <CAEemH2drL4LKRi52SQMOgVXQJSpztSKp54jRdNTkfWvPCxe34g@mail.gmail.com> (raw)
In-Reply-To: <27a48931-aff6-d001-de78-4f7bef584c32@oracle.com>

Hi Mike,

Thanks for working on this.

On Fri, Aug 2, 2019 at 8:20 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> On 7/30/19 5:44 PM, Mike Kravetz wrote:
> > A SIGBUS is the normal behavior for a hugetlb page fault failure due to
> > lack of huge pages.  Ugly, but that is the design.  I do not believe this
> > test should not be experiencing this due to reservations taken at mmap
> > time.  However, the test is combining faults, soft offline and page
> > migrations, so the there are lots of moving parts.
> >
> > I'll continue to investigate.
>
> There appears to be a race with hugetlb_fault and try_to_unmap_one of
> the migration path.
>
> Can you try this patch in your environment?  I am not sure if it will
> be the final fix, but just wanted to see if it addresses issue for you.

It works for me. After rebuilding the kernel with your patch, SIGBUS
does not appear anymore.

And I'm also thinking that why the huge_pte is not none here when race
with page migration (try_to_unmap_one).

--
Regards,
Li Wang


  parent reply	other threads:[~2019-08-02  9:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-29  5:17 [MM Bug?] mmap() triggers SIGBUS while doing the​ ​numa_move_pages() for offlined hugepage in background Li Wang
2019-07-29 19:00 ` Mike Kravetz
2019-07-30  6:29   ` Li Wang
2019-07-31  0:44     ` Mike Kravetz
2019-08-02  0:19       ` Mike Kravetz
2019-08-02  4:15         ` Naoya Horiguchi
2019-08-02 17:42           ` Mike Kravetz
2019-08-05  0:40             ` Naoya Horiguchi
2019-08-05  8:57             ` Michal Hocko
2019-08-05 17:36               ` Mike Kravetz
2019-08-07  0:07                 ` Mike Kravetz
2019-08-07  7:39                   ` Michal Hocko
2019-08-07 15:10                     ` Mike Kravetz
2019-08-02  9:59         ` Li Wang [this message]
2019-07-30  6:38   ` Li Wang
2019-08-02  3:48 ` Naoya Horiguchi

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=CAEemH2drL4LKRi52SQMOgVXQJSpztSKp54jRdNTkfWvPCxe34g@mail.gmail.com \
    --to=liwang@redhat.com \
    --cc=chrubis@suse.cz \
    --cc=linux-mm@kvack.org \
    --cc=ltp@lists.linux.it \
    --cc=mhocko@kernel.org \
    --cc=mike.kravetz@oracle.com \
    --cc=n-horiguchi@ah.jp.nec.com \
    --cc=xishi.qiuxishi@alibaba-inc.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).