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Always use m_split() in m_copyback() instead of its 

local, abridged, version.  This closes a window where
a new mbuf (n) can be inserted where n->m_next == n.
This commit is contained in:
seanb 2010-10-28 14:21:50 +00:00
parent 407cdd8a24
commit 49025bce19
1 changed files with 3 additions and 16 deletions
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19
sys/kern/uipc_mbuf.c
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@ -1,4 +1,4 @@
/* $NetBSD: uipc_mbuf.c,v 1.136 2010/05/11 20:21:56 pooka Exp $ */
/* $NetBSD: uipc_mbuf.c,v 1.137 2010/10/28 14:21:50 seanb Exp $ */
/*-
* Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
@ -62,7 +62,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.136 2010/05/11 20:21:56 pooka Exp $");
__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.137 2010/10/28 14:21:50 seanb Exp $");
#include "opt_mbuftrace.h"
#include "opt_nmbclusters.h"
@ -1346,7 +1346,7 @@ extend:
* if we're going to write into the middle of
* a mbuf, split it first.
*/
if (off > 0 && len < mlen) {
if (off > 0) {
n = m_split0(m, off, how, 0);
if (n == NULL)
goto enobufs;
@ -1390,19 +1390,6 @@ extend:
else
datap = NULL;
eatlen = n->m_len;
KDASSERT(off == 0 || eatlen >= mlen);
if (off > 0) {
KDASSERT(len >= mlen);
m->m_len = off;
m->m_next = n;
if (datap) {
m_copydata(m, off, mlen, datap);
datap += mlen;
}
eatlen -= mlen;
mp = &m->m_next;
m = m->m_next;
}
while (m != NULL && M_READONLY(m) &&
n->m_type == m->m_type && eatlen > 0) {
mlen = min(eatlen, m->m_len);