Bugfix: Deadlock in zlog_fini() while entering pthread_rwlock_wrlock() in multithreaded environment #184
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
…) in multithreaded environment
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Outdated suggestions cannot be applied.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.
The freeze happened in zlog_fini() while entering the final pthread_rwlock_wrlock(). This happens to me in a multithreaded binary.
Had a hard time to identify this deadlock. However, I did not find the root cause since all trace messages regarding entering/leaving the lock did not lead to a root cause problem.
Was initially thinking that this glibc bug could have been the root cause but the problem described there was not exactly the problem I was facing.
However the the inital pthread_rwlock_trywrlock() is mandatory to not run into the deadlock. Additionally EDEADLK and EBUSY needs to be handled correctly to prevent the lock.
With this fix it was possible for me to stop/start my application for around 26000 times over the weekend without any deadlock.