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Date: Mon, 11 Jul 2005 15:48:30 -0700 (PDT)
From: William Weston <weston@sysex.net>
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To: Ingo Molnar <mingo@elte.hu>
cc: Alistair John Strachan <s0348365@sms.ed.ac.uk>,
       linux-kernel@vger.kernel.org, Arjan van de Ven <arjanv@infradead.org>,
       "David S. Miller" <davem@redhat.com>
Subject: Re: Realtime Preemption, 2.6.12, Beginners Guide?
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On Sat, 9 Jul 2005, Ingo Molnar wrote:

> this patch reduces ip_setsockopt's stack footprint from 572 bytes to 164 
> bytes. (Note: needs review and testing as i could not excercise this 
> multicast codepath.)

This patch breaks multicast source group joins.  Here's the fix:

--- linux.old/net/ipv4/ip_sockglue.c	2005-07-11 01:50:19.000000000 -0700
+++ linux/net/ipv4/ip_sockglue.c	2005-07-11 13:54:34.000000000 -0700
@@ -738,7 +738,7 @@
 				break;
 			if (optlen != sizeof(struct group_source_req))
 				goto free_greqs_e_inval;
-			if (copy_from_user(&greqs, optval, sizeof(*greqs))) {
+			if (copy_from_user(greqs, optval, sizeof(*greqs))) {
 				err = -EFAULT;
 				goto free_greqs_break;
 			}

Cheers,
--ww