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author | Mark Johnston <markj@FreeBSD.org> | 2019-07-30 17:09:58 +0000 |
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committer | Mark Johnston <markj@FreeBSD.org> | 2019-07-30 17:09:58 +0000 |
commit | 49c3e8c8d147e0f23a41e3d7f8a6a8c1dba0c29d (patch) | |
tree | f7cc343264c7eff5b2b36668472701bf5e8e5999 /sys/conf | |
parent | 98197770c9f7c46a2cf2d50305b3f119d97a823e (diff) | |
download | src-49c3e8c8d147e0f23a41e3d7f8a6a8c1dba0c29d.tar.gz src-49c3e8c8d147e0f23a41e3d7f8a6a8c1dba0c29d.zip |
Enable witness(4) blessings.
witness has long had a facility to "bless" designated lock pairs. Lock
order reversals between a pair of blessed locks are not reported upon.
We have a number of long-standing false positive LOR reports; start
marking well-understood LORs as blessed.
This change hides reports about UFS vnode locks and the UFS dirhash
lock, and UFS vnode locks and buffer locks, since those are the two that
I observe most often. In the long term it would be preferable to be
able to limit blessings to a specific site where a lock is acquired,
and/or extend witness to understand why some lock order reversals are
valid (for example, if code paths with conflicting lock orders are
serialized by a third lock), but in the meantime the false positives
frequently confuse users and generate bug reports.
Reviewed by: cem, kib, mckusick
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21039
Notes
Notes:
svn path=/head/; revision=350450
Diffstat (limited to 'sys/conf')
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