From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Mandeep Singh Baines <msb@chromium.org>,
"Ma, Xindong" <xindong.ma@intel.com>,
Michal Hocko <mhocko@suse.cz>, Sameer Nanda <snanda@chromium.org>,
Sergey Dyasly <dserrg@gmail.com>,
"Tu, Xiaobing" <xiaobing.tu@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] initial while_each_thread() fixes
Date: Mon, 2 Dec 2013 16:34:18 +0100 [thread overview]
Message-ID: <20131202153418.GA11061@redhat.com> (raw)
In-Reply-To: <20131202152423.GA10878@redhat.com>
On 12/02, Oleg Nesterov wrote:
>
> The lockless while_each_thread() is racy and broken, almost
> every user can loop forever.
> ...
> Another problem with while_each_thread() is that it is very easy
> to use it wrongly, and oom_kill.c is the good example.
Forgot to mention, it is not necessarily safe even under task
list lock if it is used wrongly. Again, oom_kill.c is the good
example, oom_kill_process() does read_lock(&tasklist_lock) but
it doesn't verify that p is still alive.
The new for_each_thread() is much simpler in this respect, it
only needs the stable task_struct.
Oleg.
next prev parent reply other threads:[~2013-12-02 15:33 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-02 15:24 [PATCH 0/2] initial while_each_thread() fixes Oleg Nesterov
2013-12-02 15:24 ` [PATCH 1/2] introduce for_each_thread() to replace the buggy while_each_thread() Oleg Nesterov
2013-12-03 19:24 ` Sameer Nanda
2013-12-02 15:24 ` [PATCH 2/2] oom_kill: change oom_kill.c to use for_each_thread() Oleg Nesterov
2013-12-03 18:57 ` Sameer Nanda
2013-12-03 20:05 ` Oleg Nesterov
2013-12-03 20:50 ` Oleg Nesterov
2013-12-04 12:57 ` Oleg Nesterov
2013-12-02 15:34 ` Oleg Nesterov [this message]
2013-12-03 15:46 ` [PATCH 0/2] initial while_each_thread() fixes Sergey Dyasly
2013-12-03 18:52 ` Oleg Nesterov
2013-12-03 19:01 ` Oleg Nesterov
2013-12-03 16:53 ` William Dauchy
2013-12-03 20:22 ` Oleg Nesterov
2013-12-03 20:28 ` William Dauchy
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=20131202153418.GA11061@redhat.com \
--to=oleg@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=dserrg@gmail.com \
--cc=fweisbec@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mhocko@suse.cz \
--cc=msb@chromium.org \
--cc=rientjes@google.com \
--cc=snanda@chromium.org \
--cc=xiaobing.tu@intel.com \
--cc=xindong.ma@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 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.