Wez Furlong
0a831f60de
We've been troubleshooting a lockup on a system with a low core count. What we found in a stack trace was that one of the threads was blocking on the CACHE mutex in the sts logic. That mutex is intended to be short-duration in scope, managing the direct lookup or insertion into the cache, and no more. However, due to the the way that rust scopes the lifetime of the MutexGuard that is acquired from the CACHE, we were holding it across the async DNS operation that is used to validate that a cached policy is still current. This can result in a deadlock on a system with a sufficiently low core count/high enough concurrent volume of traffic to sites with MTA-STS enabled. This commit resolves this by introducing a lookup function that explicitly clones the cached policy without returning a MutexGuard.
KumoMTA
KumoMTA is an open-source Message Transfer Agent (MTA) designed for high-performance outbound email functionality, similar to commercial enterprise MTAs such as Momentum, PowerMTA, and Halon.
The KumoMTA project was founded by a group of email industry veterans with decades of experience building and managing high-performance On-Prem MTAs and is supported by a community of some of the largest senders in the world.
Because it is designed for high-performance sending environments, KumoMTA is for experienced email operations professionals who are accustomed to high-performance sending environments and familiar with DevOps practices.
Learn more in our FAQ.
Documentation
You can learn more about KumoMTA from the Documentation.
Community
Real-time discussion is available on Our Discord.
Developers
If you are interested in contributing/extending KumoMTA, take a look at DEVELOPERS.md. The #devel channel on Our Discord is for contributors to discuss KumoMTA development.
Reporting Bugs
See How to Report Bugs.
Getting Help
See How to Get Help.
Talk to Us
We're available to talk about the project, book us at https://cal.com/team/kumomta/talk-with-kumomta.