Fix lock cycle (un)registering asok commands #7581
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
added 2 commits
February 9, 2016 12:18
Otherwise, hooks cannot take any locks which were held during registration of hooks, because it creates a cycle. Signed-off-by: John Spray <john.spray@redhat.com>
unregister blocks until any running hook has completed, and that running hook might be one that takes the objecter lock, so you can't hold it while unregistering. Signed-off-by: John Spray <john.spray@redhat.com>
|
Related test: ceph/ceph-qa-suite#805 |
liewegas
added a commit
that referenced
this pull request
Feb 11, 2016
librados: mix lock cycle (un)registering asok commands Reviewed-by: Sage Weil <sage@redhat.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Previously, in e.g. Objecter, we had hooks that went AdminSocket::m_lock -> Objecter::rwlock, and then during shutdown, calls to unregister resulted in the opposite lock order. That was genuinely dangerous (not just lockdep noise) because there was nothing stopping a user sending a command at the moment of shutdown and causing a deadlock.