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Revision db61ecc3352d72513c1b07805bd6f760e30c001b authored by Tommy S. Christensen on 19 May 2005, 19:46:59 UTC, committed by David S. Miller on 19 May 2005, 19:46:59 UTC 
[NETLINK]: Fix race with recvmsg().
 
This bug causes:

assertion (!atomic_read(&sk->sk_rmem_alloc)) failed at net/netlink/af_netlink.c (122)

What's happening is that:

1) The skb is sent to socket 1.
2) Someone does a recvmsg on socket 1 and drops the ref on the skb.
   Note that the rmalloc is not returned at this point since the
   skb is still referenced.
3) The same skb is now sent to socket 2.

This version of the fix resurrects the skb_orphan call that was moved
out, last time we had 'shared-skb troubles'. It is practically a no-op
in the common case, but still prevents the possible race with recvmsg.

Signed-off-by: Tommy S. Christensen <tommy.christensen@tpack.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 1eda339
Raw File
wanbook.tmpl 
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
	"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>

<book id="WANGuide">
 <bookinfo>
  <title>Synchronous PPP and Cisco HDLC Programming Guide</title>
  
  <authorgroup>
   <author>
    <firstname>Alan</firstname>
    <surname>Cox</surname>
    <affiliation>
     <address>
      <email>alan@redhat.com</email>
     </address>
    </affiliation>
   </author>
  </authorgroup>

  <copyright>
   <year>2000</year>
   <holder>Alan Cox</holder>
  </copyright>

  <legalnotice>
   <para>
     This documentation is free software; you can redistribute
     it and/or modify it under the terms of the GNU General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later
     version.
   </para>
      
   <para>
     This program is distributed in the hope that it will be
     useful, but WITHOUT ANY WARRANTY; without even the implied
     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     See the GNU General Public License for more details.
   </para>
      
   <para>
     You should have received a copy of the GNU General Public
     License along with this program; if not, write to the Free
     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
     MA 02111-1307 USA
   </para>
      
   <para>
     For more details see the file COPYING in the source
     distribution of Linux.
   </para>
  </legalnotice>
 </bookinfo>

<toc></toc>

  <chapter id="intro">
      <title>Introduction</title>
  <para>
	The syncppp drivers in Linux provide a fairly complete 
	implementation of Cisco HDLC and a minimal implementation of
	PPP. The longer term goal is to switch the PPP layer to the
	generic PPP interface that is new in Linux 2.3.x. The API should
	remain unchanged when this is done, but support will then be
	available for IPX, compression and other PPP features
  </para>
  </chapter>
  <chapter id="bugs">
     <title>Known Bugs And Assumptions</title>
  <para>
  <variablelist>
    <varlistentry><term>PPP is minimal</term>
    <listitem>
    <para>
	The current PPP implementation is very basic, although sufficient
	for most wan usages.
    </para>
    </listitem></varlistentry>

    <varlistentry><term>Cisco HDLC Quirks</term>
    <listitem>
    <para>
	Currently we do not end all packets with the correct Cisco multicast
	or unicast flags. Nothing appears to mind too much but this should
	be corrected.
    </para>
    </listitem></varlistentry>
  </variablelist>
	
  </para>
  </chapter>

  <chapter id="pubfunctions">
     <title>Public Functions Provided</title>
!Edrivers/net/wan/syncppp.c
  </chapter>

</book>
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