FreeBSD src
a787e5ecf8
routines to guard against problems caused by (possibly) buggy drivers. The RealTek 8180 wireless driver calls NdisFreeBuffer() to release some of its buffers _after_ it's already called NdisFreeBufferPool() to destroy the pool to which the buffers belong. In our implementation, this error causes NdisFreeBuffer() to touch stale heap memory. If you are running a release kernel, and hence have INVARIANTS et al turned off, it turns out nothing happens. But if you're using a development kernel config with INVARIANTS on, the malloc()/free() sanity checks will scribble over the pool memory with 0xdeadc0de once it's released so that any attempts to touch it will cause a trap, and indeed this is what happens. It happens that I run 5.2-RELEASE on my laptop, so when I tested the rtl8180.sys driver, it worked fine for me, but people trying to run it with development systems checked out or cvsupped from -current would get a page fault on driver load. I can't find any reason why the NDISulator would cause the RealTek driver to do the NdisFreeBufferPool() prematurely, and the same driver obviously works with Windows -- or at least, it doesn't cause a crash: the Microsoft documentation for NdisFreeBufferPool() says that failing to return all buffers to the pool before calling NdisFreeBufferPool() causes a memory leak. I've written to my contacts at RealTek asking them to check if this is indeed a bug in their driver. In the meantime, these new sanity checks will catch this problem and issue a warning rather than causing a trap. The trick is to keep a count of outstanding buffers for each buffer pool, and if the driver tries to call NdisFreeBufferPool() while there are still buffers outstanding, we mark the pool for deletion and then defer destroying it until after the last buffer has been reclaimed. |
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| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| installworld_newk | ||
| installworld_oldk | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| README | ||
| UPDATING | ||
| UPDATING.64BTT | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html