From: Andi Kleen <andi@firstfloor.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Andi Kleen <ak@linux.intel.com>, Andi Kleen <andi@firstfloor.org>,
jmorris@namei.org, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] SMACK: Add missing rcu_read_lock/unlock for process capability walk.
Date: Thu, 21 Apr 2011 02:08:18 +0200 [thread overview]
Message-ID: <20110421000818.GT16484@one.firstfloor.org> (raw)
In-Reply-To: <4DAF6FA5.7080801@schaufler-ca.com>
> The global list, yes. The task specific list, no. Modifying the local
> list is like any other modification of the cred structure and requires
> the cred be copied.
But you still need to free it eventually right? And that freeing will
need RCU on the reader.
>
> Moving the lock into smk_access_entry() would introduce a potential
> deadlock in smack_mmap_file. There is a bit of convolution in the
> mmap hook that requires looking at the list in a way that does not
> allow the locking to be embedded where it used to be.
rcu_read_lock() is just a per task counter and nests fine and never deadlocks.
-Andi
next prev parent reply other threads:[~2011-04-21 0:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-20 22:00 [PATCH] SMACK: Add missing rcu_read_lock/unlock for process capability walk Andi Kleen
2011-04-20 22:51 ` Casey Schaufler
2011-04-20 23:18 ` Andi Kleen
2011-04-20 23:43 ` Casey Schaufler
2011-04-21 0:08 ` Andi Kleen [this message]
2011-04-21 0:47 ` Casey Schaufler
2011-04-21 15:58 ` Andi Kleen
2011-04-22 3:55 ` Casey Schaufler
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=20110421000818.GT16484@one.firstfloor.org \
--to=andi@firstfloor.org \
--cc=ak@linux.intel.com \
--cc=casey@schaufler-ca.com \
--cc=jmorris@namei.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
/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