diff options
| author | David Gwynne <dlg@cvs.openbsd.org> | 2018-03-12 23:38:43 +0000 |
|---|---|---|
| committer | David Gwynne <dlg@cvs.openbsd.org> | 2018-03-12 23:38:43 +0000 |
| commit | c00a96d579b9d3862021a72d5dd290100c0a8b8f (patch) | |
| tree | bfc05354abf708f23b141cc0be7315901069155f /sys | |
| parent | 167f49617df84eb257a060c7c996b1fd6dd5447b (diff) | |
make m_adj keep m_data aligned when removing all the data in an mbuf.
previously it took a shortcut when emptying an mbuf by only setting
m_len to 0, but leaving m_data alone. this interacts badly with
m_pullup, which tries to maintain the alignment of the data
payload. if there was a 14 byte ethernet header on its own that was
m_adjed off, and then the stack wants an ip header, m_pullup
would put the ip header on the ethernet header alignment, which is
off by 2 bytes.
found by stsp@ with pair(4) on sparc64.
ok stsp@ too
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/kern/uipc_mbuf.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c index 13a1a3fad53..5535225f60f 100644 --- a/sys/kern/uipc_mbuf.c +++ b/sys/kern/uipc_mbuf.c @@ -1,4 +1,4 @@ -/* $OpenBSD: uipc_mbuf.c,v 1.253 2018/01/16 19:44:34 benno Exp $ */ +/* $OpenBSD: uipc_mbuf.c,v 1.254 2018/03/12 23:38:42 dlg Exp $ */ /* $NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $ */ /* @@ -812,11 +812,12 @@ m_adj(struct mbuf *mp, int req_len) while (m != NULL && len > 0) { if (m->m_len <= len) { len -= m->m_len; + m->m_data += m->m_len; m->m_len = 0; m = m->m_next; } else { - m->m_len -= len; m->m_data += len; + m->m_len -= len; len = 0; } } |