Date: Sun, 20 Jul 2003 20:12:06 -0700 (PDT) From: Mike Silbersack <silby@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/kern uipc_mbuf.c Message-ID: <200307210312.h6L3C6MA082887@repoman.freebsd.org>
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silby 2003/07/20 20:12:06 PDT
FreeBSD src repository
Modified files: (Branch: RELENG_4)
sys/kern uipc_mbuf.c
Log:
Add in the promised cluster refcount limit hack. (Not applicable to
-current, which has int size refcounts.)
4.x uses char refcounts, which can be overflowed, causing neat panics.
This patch works around the problem by hooking into every m_* function
that increases the refcount and doing two things:
1. Panicing if the refcount went negative (perhaps due to some external
function messing with the refcount.)
2. Making a full copy of the resulting chain in order to keep the
refcount under a reasonable threshold if necessary.
The kern.ipc.m_clreflimithits sysctl has been made available so that
the number of times a copy had to be performed can be monitored. Luckily,
this should not be a common occurance.
Revision Changes Path
1.51.2.29 +43 -0 src/sys/kern/uipc_mbuf.c
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