CVS commit: src/sys/kern

["Maxime Villard" <maxv%netbsd.org@localhost>]

Module Name:    src
Committed By:   maxv
Date:           Sun Dec 31 06:57:12 UTC 2017

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

Log Message:
Check MT_FREE by default, and not just under DEBUG (or DIAGNOSTIC). This
code is fast, with an nonexistent overhead - and we already take care of
setting MT_FREE, so why not check it.

In addition, stop registering the function name, that's not helpful since
the MBUFFREE macro is local. Instead, set m_data to NULL, so that any
access to a freed mbuf's data after mtod() or similar will page fault.

The combination of these two changes provides a fast and efficient way of
detecting use-after-frees in the network stack.


To generate a diff of this commit:
cvs rdiff -u -r1.173 -r1.174 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.