From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org, ebiederm@xmission.com
Subject: Re: [PATCH] [1/11] Add rcustring ADT for RCU protected strings
Date: Tue, 22 Dec 2009 12:59:12 -0800 [thread overview]
Message-ID: <20091222205912.GD9279@linux.vnet.ibm.com> (raw)
In-Reply-To: <20091222100553.GA10314@basil.fritz.box>
On Tue, Dec 22, 2009 at 11:05:53AM +0100, Andi Kleen wrote:
> On Mon, Dec 21, 2009 at 06:46:35PM -0800, Paul E. McKenney wrote:
> > My guess is that you will sooner or later need a size field, perhaps
> > under some debug config parameter.
>
> That can be gotten from ksize() if needed.
Fair enough!!!
> > > +/*
> > > + * Get a local private copy of a RCU protected string.
> > > + * Mostly useful to get a string that is stable while sleeping.
> > > + * Caller must free returned string.
> > > + */
> > > +char *access_rcu_string(const char *str, int size, gfp_t gfp)
> > > +{
> > > + char *copy = kmalloc(size, gfp);
> > > + if (!str)
> > > + return NULL;
> >
> > Assuming that "str" points to the "str" field of a struct rcu_string,
> > what prevents a grace period from elapsing at this point, freeing the
> > "str" out from under us?
>
> Yes, that's broken thanks. I'll move the reference into the read lock
> section.
Looking forward to seeing the updated version!
Thanx, Paul
next prev parent reply other threads:[~2009-12-22 20:59 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-21 1:20 [PATCH] [0/11] SYSCTL: Use RCU to avoid races with string sysctls Andi Kleen
2009-12-21 1:20 ` [PATCH] [1/11] Add rcustring ADT for RCU protected strings Andi Kleen
2009-12-22 2:46 ` Paul E. McKenney
2009-12-22 10:05 ` Andi Kleen
2009-12-22 20:59 ` Paul E. McKenney [this message]
2009-12-21 1:20 ` [PATCH] [2/11] Add a kernel_address() that works for data too Andi Kleen
2009-12-21 1:20 ` [PATCH] [3/11] SYSCTL: Add proc_rcu_string to manage sysctls using rcu strings Andi Kleen
2009-12-22 2:51 ` Paul E. McKenney
2009-12-22 3:00 ` Eric W. Biederman
2009-12-22 7:44 ` Paul E. McKenney
2009-12-21 1:20 ` [PATCH] [4/11] SYSCTL: Use RCU strings for core_pattern sysctl Andi Kleen
2009-12-21 1:20 ` [PATCH] [5/11] SYSCTL: Add call_usermodehelper_cleanup() Andi Kleen
2009-12-21 1:20 ` [PATCH] [6/11] SYSCTL: Convert modprobe_path to proc_rcu_string() Andi Kleen
2009-12-21 1:20 ` [PATCH] [7/11] SYSCTL: Convert poweroff_command to proc_rcu_string Andi Kleen
2009-12-21 1:20 ` [PATCH] [8/11] SYSCTL: Convert hotplug helper string to proc_rcu_string() Andi Kleen
2009-12-22 19:03 ` Greg KH
2009-12-21 1:20 ` [PATCH] [9/11] SYSCTL: Add a mutex to the page_alloc zone order sysctl Andi Kleen
2009-12-21 1:20 ` [PATCH] [10/11] SYSCTL: Use RCU protected sysctl for ocfs group add helper Andi Kleen
2009-12-21 1:20 ` [PATCH] [11/11] SYSCTL: Convert IRDA text sysctl to RCU Andi Kleen
2009-12-21 1:59 ` [PATCH] [0/11] SYSCTL: Use RCU to avoid races with string sysctls Eric W. Biederman
2009-12-21 2:04 ` Andi Kleen
2009-12-21 2:31 ` Eric W. Biederman
2009-12-21 3:21 ` Andi Kleen
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=20091222205912.GD9279@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=andi@firstfloor.org \
--cc=ebiederm@xmission.com \
--cc=linux-kernel@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