From: Andrew Morton <akpm@linux-foundation.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: chrisw@sous-sol.org, roland@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] ptrace: ptrace_attach: check PF_KTHREAD + exit_state instead of ->mm
Date: Tue, 5 May 2009 16:47:33 -0700 [thread overview]
Message-ID: <20090505164733.54cd4ca4.akpm@linux-foundation.org> (raw)
In-Reply-To: <20090505224722.GA954@redhat.com>
On Wed, 6 May 2009 00:47:22 +0200
Oleg Nesterov <oleg@redhat.com> wrote:
> - Add PF_KTHREAD check to prevent attaching to the kernel thread
> with a borrowed ->mm.
>
> With or without this change we can race with daemonize() which
> can set PF_KTHREAD or clear ->mm after ptrace_attach() does the
> check, but this doesn't matter because reparent_to_kthreadd()
> does ptrace_unlink().
>
> - Kill "!task->mm" check. We don't really care about ->mm != NULL,
> and the task can call exit_mm() right after we drop task_lock().
> What we need is to make sure we can't attach after exit_notify(),
> check task->exit_state != 0 instead.
>
These patches make a mess of utrace-core.patch. Do we really want to do that?
next prev parent reply other threads:[~2009-05-05 23:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-05 22:47 [PATCH 1/3] ptrace: ptrace_attach: check PF_KTHREAD + exit_state instead of ->mm Oleg Nesterov
2009-05-05 23:47 ` Andrew Morton [this message]
2009-05-05 23:57 ` Oleg Nesterov
2009-05-06 1:24 ` Andrew Morton
2009-05-06 2:06 ` Roland McGrath
2009-05-06 4:56 ` Oleg Nesterov
2009-05-06 5:03 ` Andrew Morton
2009-05-06 7:08 ` Christoph Hellwig
2009-05-06 7:41 ` Ingo Molnar
2009-05-06 2:02 ` Roland McGrath
2009-05-06 4:52 ` Oleg Nesterov
2009-05-07 5:51 ` Roland McGrath
2009-05-09 18:43 ` Oleg Nesterov
2009-05-10 23:11 ` Roland McGrath
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=20090505164733.54cd4ca4.akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=chrisw@sous-sol.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=roland@redhat.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.