On 10 Jan 2018, at 17.28, Jason Kiniry jason@cpanel.net wrote:
When in the process of testing out the 2.3.0 version of Dovecot, we noticed that on a busy server, imap-login can sometimes take 100% CPU and remain there indefinitely. We grabbed a gdb trace while it was happening:
dovenull 36053 31.2 0.0 60460 17316 ? R 04:38 11:55 dovecot/imap-login root@server [~]# strace -p 36053 Process 36053 attached ^CProcess 36053 detached
So it's not doing any syscalls. What about ltrace -tt -e '*' -p <pid>?
Also what's your doveconf -n? Mainly wondering about service imap-login { .. } settings. Probably service_count=1 (default)? This somehow hangs here when there's a client with pending input, but auth process wasn't yet connected to. It's not very obvious though how it could have gotten stuck in there.