smtp crashing with "out of memory" for ONE particular user

Jacek Osiecki dovejosh at
Tue Apr 24 09:08:41 EEST 2018


I’m using dovecot 2.0.16 (I know, it’s oooold, but I have too many users to risk the upgrade while so many things have changed since)
and virtual users based on MySQL.

Today I had some troubles with user, who’s mailbox stopped working. No emails were delivered,
with just following error line in EXIM mainlog:

LMTP connection closed after end of data

When I checked dovecot’s main log, and here’s what I found:

Apr 23 14:06:17 lmtp(9963, jmk at Fatal: block_alloc(67108864): Out of memory
Apr 23 14:06:17 lmtp(9963, jmk at Error: Raw backtrace: /usr/lib64/dovecot/ [0x7f92f3193bda] -> /usr/lib64/dovecot/ [0x7f92f3193c1e] -> /usr
/lib64/dovecot/ [0x7f92f316d8cd] -> /usr/lib64/dovecot/ [0x7f92f31a2c45] -> /usr/lib64/dovecot/ [0x7f92f31a2c7f] -> /usr/lib64/
dovecot/ [0x7f92f31ae08e] -> /usr/lib64/dovecot/ [0x7f92f3653e69] -> /usr/lib64/dovecot/
ildir_uidlist_sync_next+0x12) [0x7f92f3654232] -> /usr/lib64/dovecot/ [0x7f92f3651d3a] -> /usr/lib64/dovecot/ [0x7f92f36527d3] -> /usr/li
b64/dovecot/ [0x7f92f3652d91] -> /usr/lib64/dovecot/ [0x7f92f36173a1] -> /usr/lib64/dovecot/libdovec [0x7f92f36174b7] -> /usr/lib64/dovecot/plugins/ [0x7f92f1f34fe2] -> /usr/lib64/dovecot/plugins/ [0
x7f92f1f36430] -> /usr/lib64/dovecot/plugins/ [0x7f92f1f3663d] -> /usr/lib64/dovecot/plugins/ [0x7f92f1f344c2] -> /usr/lib64/do
vecot/plugins/ [0x7f92f1f34d45] -> /usr/lib64/dovecot/plugins/ [0x7f92f1f390ba] -> /usr/lib64/dovecot/
ilbox_save_begin+0x46) [0x7f92f3617f56] -> /usr/lib64/dovecot/ [0x7f92f361100e] -> /usr/lib64/dovecot/ [0x7f92f364
a8a1] -> /usr/lib64/dovecot/plugins/ [0x7f92f1f38efa] -> /usr/lib64/dovecot/ [0x7f92f3617eba] -> /usr/lib64/dovecot/libdovecot-siev [0x7f92f1ae9ed6] -> /usr/lib64/dovecot/ [0x7f92f1ae083c] -> /usr/lib64/dovecot/ [0x7f92f1ae1a0d] -> /usr/l
ib64/dovecot/ [0x7f92f1af0a9d]
Apr 23 14:06:17 master: Error: service(lmtp): child 9963 returned error 83 (Out of memory (vsz_limit=256 MB, you may need to increase it))

What was interesting - it happenned only with this particular mailbox. It does not has large sieve file (actually, other mailboxes have muuuch bigger ones,
actually nothing strange with the account - but it was failing.
I have increased vsz_limit to 384MB - didn’t help.

Finally, 512MB helped. But it is quite strange to me… Why one particular mailbox, what could be causing it?

Jacek Osiecki
josiecki at

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