Update the lock-order-reversal question

PR:		docs/174226
Submitted by:	Bas Smeelen <b.smeelen@ose.nl>
Reviewed by:	Erich Dollansky <erichsfreebsdlist@alogt.com>
Reviewed by:	avg
Reviewed by:	bjk
Discussed with:	wblock
Approved by:	??? (mentor)
This commit is contained in:
Eitan Adler 2013-02-23 14:50:24 +00:00
parent a212cc6dcd
commit 35e440b853
Notes: svn2git 2020-12-08 03:00:23 +00:00
svn path=/head/; revision=41036

View file

@ -2493,9 +2493,19 @@ kern.timecounter.hardware: TSC -&gt; i8254</screen>
</question>
<answer>
<para>An answer for this question can be found in the &os;
Glossary, see <ulink
url="&url.books.handbook;/freebsd-glossary.html#lor-glossary">LOR</ulink>.</para>
<para>The &os; kernel uses a number of resource locks to
arbitrate contention for certain resources. A run-time
lock diagnostic system found in &os.current; kernels
(but removed for releases), called &man.witness.4;,
detects the potential for deadlocks due to locking errors.
(It is possible to get false positives, as &man.witness.4;
is slightly conservative.) A true positive report
indicates that "if you were unlucky, a deadlock would have
happened here">.</para>
<para>Problematic <acronym>LOR</acronym>s tend to get fixed
quickly, so check &a.current.url; before posting to the
mailing lists.</para>
</answer>
</qandaentry>