All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: Muchun Song <songmuchun@bytedance.com>
Cc: mike.kravetz@oracle.com, npiggin@suse.de, agl@us.ibm.com,
	ak@linux.intel.com, nacc@us.ibm.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/hugetlb: Fix a race between hugetlb sysctl handlers
Date: Mon, 24 Aug 2020 13:59:24 -0700	[thread overview]
Message-ID: <20200824135924.b485e000d358cee817c4f05c@linux-foundation.org> (raw)
In-Reply-To: <20200822095328.61306-1-songmuchun@bytedance.com>

On Sat, 22 Aug 2020 17:53:28 +0800 Muchun Song <songmuchun@bytedance.com> wrote:

> There is a race between the assignment of `table->data` and write value
> to the pointer of `table->data` in the __do_proc_doulongvec_minmax().

Where does __do_proc_doulongvec_minmax() write to table->data?

I think you're saying that there is a race between the assignment of
ctl_table->table in hugetlb_sysctl_handler_common() and the assignment
of the same ctl_table->table in hugetlb_overcommit_handler()?

Or not, maybe I'm being thick.  Can you please describe the race more
carefully and completely?

> Fix this by duplicating the `table`, and only update the duplicate of
> it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to
> simplify the code.
> 


  reply	other threads:[~2020-08-24 20:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-22  9:53 [PATCH] mm/hugetlb: Fix a race between hugetlb sysctl handlers Muchun Song
2020-08-24 20:59 ` Andrew Morton [this message]
2020-08-24 21:19   ` Mike Kravetz
2020-08-25  3:01     ` [External] " Muchun Song
2020-08-25  3:01       ` Muchun Song
2020-08-26  0:01       ` Mike Kravetz
2020-08-26  2:47         ` Muchun Song
2020-08-26  2:47           ` Muchun Song
2020-08-27 21:51           ` Mike Kravetz
2020-08-28  2:33             ` Muchun Song
2020-08-28  2:33               ` Muchun Song
2020-08-25  2:42 ` Muchun Song
2020-08-25  2:42   ` Muchun Song
2020-08-25 15:25 ` Andi Kleen
2020-08-26  2:34   ` [Phishing Risk] [External] " Muchun Song
2020-08-26  2:34     ` Muchun Song

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=20200824135924.b485e000d358cee817c4f05c@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=agl@us.ibm.com \
    --cc=ak@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mike.kravetz@oracle.com \
    --cc=nacc@us.ibm.com \
    --cc=npiggin@suse.de \
    --cc=songmuchun@bytedance.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.