Millions of journal entries "end-of-input while reading request from tlsmgr socket"

[Lio Lunesu]

Hi!

I've running postfix 3.6.2 for over a month now, but suddenly today my machine became unresponsive and I had to do a hard reboot. Inspecting the journal I'm noticing *millions* of identical log messages:

postfix/tlsmgr[109663]: warning: end-of-input while reading request from tlsmgr socket: Application error

Counting these messages using `journalctl -u postfix | uniq -c` shows they come in bursts of 20k-30k, twice a minute (every 30s).

This looks like a race condition, where a closed socket (because of OOM or some other condition?) a socket gets closed but tlsmgr gets into a loop trying to read a string for a broken socket?

The offending line is here: https://github.com/vdukhovni/postfix/blob/1f2df46e5211065a16f78739308131122e185c7c/postfix/src/tlsmgr/tlsmgr.c#L576

How do I go about debugging this? What application does the "Application Error" refer to?

Thanks,

Lio