SIGSEGV in cyrus-imapd 3.0.7 mupdate

[Michael Menge]

Hi,

we are in the process of setting up our new production mailserver with
cyrus-imapd 3.0.7 on RHEL 7.5 Servers.

At the moment we encounter many crashes (SIGSEGV) of the mupdate process on
the mupdate master instance. As soon as we issue a command that updates
multiple mailboxes in short time we trigger a SIGSEGV.

> sam user/zrstes* cyrus all
Setting ACL on user/zrstes1...OK.
Setting ACL on user/zrstes1/Mail...OK.
Setting ACL on user/zrstes1/Mail/drafts...OK.
Setting ACL on user/zrstes1/Mail/s-spam...OK.
Setting ACL on user/zrstes1/Mail/sent...OK.
Setting ACL on user/zrstes1/Mail/trash...OK.
Setting ACL on user/zrstes1/Mail/v-spam...OK.
Setting ACL on user/zrstes2...cyrus: lrswipkxtea: no connection to server

I suspect that at this time the connection from the backend to the  
mupdate master
is lost as the mupdate process received the SIGSEGV

(gdb) bt
#0  0x00007fb49c000098 in ?? ()
#1  0x00007fb4a9a59a85 in DH_free (r=0x7fb49c1b9600) at dh_lib.c:194
#2  0x00007fb4aa84dbef in tls_shutdown_serverengine () at imap/tls.c:1311
#3  0x0000000000404075 in conn_free (C=0x7fb4840009f0) at imap/mupdate.c:379
#4  0x00000000004062c0 in thread_main (rock=0x0) at imap/mupdate.c:1330
#5  0x00007fb4a771add5 in start_thread (arg=0x7fb4a22d9700) at  
pthread_create.c:308
#6  0x00007fb4a718fb3d in clone () at  
../sysdeps/unix/sysv/linux/x86_64/clone.S:113


Further information, as DH_free is in the bt, we have NOT configured  
dh_params in
our ssl certificate/key or in the imapd.conf

Kind regards

    Michael Menge

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