CVS commit: src/sys/kern

["Ryota Ozaki" <ozaki-r%netbsd.org@localhost>]

Module Name:    src
Committed By:   ozaki-r
Date:           Mon Nov 27 02:50:27 UTC 2023

Modified Files:
        src/sys/kern: uipc_mbuf.c

Log Message:
mbuf: avoid assertion failure when splitting mbuf cluster

>From OpenBSD:

        commit 7b4d35e0a60ba1dd4daf4b1c2932020a22463a89
        Author: bluhm <bluhm%openbsd.org@localhost>
        Date:   Fri Oct 20 16:25:15 2023 +0000

            Avoid assertion failure when splitting mbuf cluster.

            m_split() calls m_align() to initialize the data pointer of newly
            allocated mbuf.  If the new mbuf will be converted to a cluster,
            this is not necessary.  If additionally the new mbuf is larger than
            MLEN, this can lead to a panic.
            Only call m_align() when a valid m_data is needed.  This is the
            case if we do not refecence the existing cluster, but memcpy() the
            data into the new mbuf.

            Reported-by: syzbot+0e6817f5877926f0e96a%syzkaller.appspotmail.com@localhost
            OK claudio@ deraadt@

The issue is harmless if DIAGNOSTIC is not enabled.

XXX pullup-10
XXX pullup-9


To generate a diff of this commit:
cvs rdiff -u -r1.251 -r1.252 src/sys/kern/uipc_mbuf.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.