From f449396167e2de3dd281b2134d0c9a7ba76a275d Mon Sep 17 00:00:00 2001 From: silby Date: Fri, 2 May 2003 03:43:40 +0000 Subject: Add the M_FREELIST flag, which is used to detect whenever a double free of a mbuf occurs and cause an immediate panic, rather than allowing free list corruption to occur. This code is trapped under INVARIANTS, so it should not cause any change in default performance. Reviewed by: a bunch of people on -net MFC after: 1 week --- sys/kern/subr_mbuf.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'sys/kern/subr_mbuf.c') diff --git a/sys/kern/subr_mbuf.c b/sys/kern/subr_mbuf.c index 5d593e6..5d624f6 100644 --- a/sys/kern/subr_mbuf.c +++ b/sys/kern/subr_mbuf.c @@ -1380,6 +1380,11 @@ m_free(struct mbuf *mb) int cchnum; short persist = 0; +#ifdef INVARIANTS + if (mb->m_flags & M_FREELIST) + panic("m_free detected a mbuf double-free"); + mb->m_flags |= M_FREELIST; +#endif if ((mb->m_flags & M_PKTHDR) != 0) m_tag_delete_chain(mb, NULL); nb = mb->m_next; @@ -1422,6 +1427,11 @@ m_freem(struct mbuf *mb) short persist; while (mb != NULL) { +#ifdef INVARIANTS + if (mb->m_flags & M_FREELIST) + panic("m_freem detected a mbuf double-free"); + mb->m_flags |= M_FREELIST; +#endif if ((mb->m_flags & M_PKTHDR) != 0) m_tag_delete_chain(mb, NULL); persist = 0; -- cgit v1.1