lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Thu, 28 Feb 2008 10:39:55 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	"Hawkes Steve-FSH016" <Steve.Hawkes@...orola.com>
Cc:	<davem@...emloft.net>, <joe@...ches.com>,
	<linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: Re: printk_ratelimit and net_ratelimit conflict and tunable
 behavior

On Thu, 28 Feb 2008 10:19:02 -0600 "Hawkes Steve-FSH016" <Steve.Hawkes@...orola.com> wrote:

> Andrew Morton wrote:
> 
> > This patch causes a large and nasty reject.
> > Probably because you patched 2.6.24.  We're developing 2.6.25 now, and
> > the difference between the two is very large inded.  Please raise
> patches
> > against Linus's latest tree?
> 
> Will do. I'm learning the process. I assume Linus's latest tree is the
> one
> listed as the latest prepatch for the stable Linux kernel tree.

No, the stable tree is 2.6.24.  You'll want
ftp://ftp.kernel.org/pub/linux/kernel/v2.6/snapshots/

> > >  int net_ratelimit(void)
> > >  {
> > > -	return __printk_ratelimit(net_msg_cost, net_msg_burst);
> > > +	static struct printk_ratelimit_state limit_state = {
> > > +		.toks          = 10 * 5 * HZ,
> > > +		.last_jiffies  = 0,
> > > +		.missed        = 0,
> > > +		.limit_jiffies = 5 * HZ,
> > > +		.limit_burst   = 10,
> > > +		.facility      = "net"
> > > +	};
> > > +
> > > +	return __printk_ratelimit(net_msg_cost, net_msg_burst,
> &limit_state);
> > 
> > I don't get it.  There's one instance of limit_state, kernel-wide, and
> > __printk_ratelimit() modifies it.  What prevents one CPU's activities
> from
> > interfering with a second CPU's activities?
> 
> The state is protected by the spinlock in __printk_ratelimit, like it is
> in
> the current kernel. Am I missing something?

ah, OK.

I've occasionally wondered if ratelimiting should be per-callsite rather
than kernel-wide, but I'm not aware of the present setup causing anyone any
problems.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists