[Dovecot] dovecot-imapd eating 100% cpu every once in a while

Robert Schetterer rs at sys4.de
Wed Dec 11 20:26:13 EET 2013


Am 11.12.2013 18:10, schrieb Nikolaus Rath:
> Hello,
> 
> *ping*

backping upgrade to 2.1.17, perhaps bug is allready fixed

> 
> Really no one able to help with the issue below?
> 
> Best,
> Nikolaus
> 
> 
> Nikolaus Rath <Nikolaus at rath.org> writes:
>> Hello,
>>
>> About once or twice a week, dovecot's imap-login process on my system
>> seems gets out of control, eating 100% CPU for about 2 hours. Afterwards
>> everything seems to go back to normal.
>>
>> I am using Dovecot 2.1.7 on a 64 bit Debian wheezy system.
>>
>> When running gdb on the process in this stage, I get the following
>> traceback:
>>
>> #0  0x00007fcba50c5a90 in read () from /lib/x86_64-linux-gnu/libc.so.6
>> #1  0x00007fcba4aa01aa in ?? () from /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.0
>> #2  0x00007fcba4a9df09 in BIO_read () from /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.0
>> #3  0x00007fcba4dbac8c in ?? () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
>> #4  0x00007fcba4dbbe75 in ?? () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
>> #5  0x00007fcba4dbd8d0 in ?? () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
>> #6  0x00007fcba4dad07a in ?? () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
>> #7  0x00007fcba4db143b in ?? () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
>> #8  0x00007fcba5622b61 in ssl_handshake (proxy=0x7fcba7870bb0) at ssl-proxy-openssl.c:465
>> #9  ssl_step (proxy=0x7fcba7870bb0) at ssl-proxy-openssl.c:528
>> #10 0x00007fcba53d2016 in io_loop_call_io (io=0x7fcba786fc80) at ioloop.c:379
>> #11 0x00007fcba53d2cc7 in io_loop_handler_run (ioloop=ioloop at entry=0x7fcba778c6e0)
>>     at ioloop-epoll.c:213
>> #12 0x00007fcba53d1a28 in io_loop_run (ioloop=0x7fcba778c6e0) at ioloop.c:398
>> #13 0x00007fcba53be483 in master_service_run (service=0x7fcba778c590, 
>>     callback=callback at entry=0x7fcba5620100 <client_connected>) at master-service.c:544
>> #14 0x00007fcba562079e in login_binary_run (binary=<optimized out>, argc=1, argv=0x7fcba778c370)
>>     at main.c:406
>> #15 0x00007fcba5015ead in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
>> #16 0x00007fcba5a52b2d in _start ()
>>
>> strace -tt says:
>>
>> 16:14:19.693378 gettimeofday({1381421659, 693415}, NULL) = 0
>> 16:14:19.693490 time(NULL)              = 1381421659
>> 16:14:19.693588 read(18, 0x7fcba7876a43, 5) = -1 EAGAIN (Resource temporarily unavailable)
>> 16:14:19.693688 epoll_wait(14, {{EPOLLOUT, {u32=2810463600, u64=140512665552240}}}, 10, 4294967295) = 1
>> 16:14:19.693796 gettimeofday({1381421659, 693823}, NULL) = 0
>> 16:14:19.693890 time(NULL)              = 1381421659
>> 16:14:19.693984 read(18, 0x7fcba7876a43, 5) = -1 EAGAIN (Resource temporarily unavailable)
>> 16:14:19.694084 epoll_wait(14, {{EPOLLOUT, {u32=2810463600, u64=140512665552240}}}, 10, 4294967295) = 1
>> 16:14:19.694177 gettimeofday({1381421659, 694203}, NULL) = 0
>> 16:14:19.694269 time(NULL)              = 1381421659
>> 16:14:19.694399 read(18, 0x7fcba7876a43, 5) = -1 EAGAIN (Resource temporarily unavailable)
>> 16:14:19.694563 epoll_wait(14, {{EPOLLOUT, {u32=2810463600, u64=140512665552240}}}, 10, 4294967295) = 1
>> 16:14:19.694706 gettimeofday({1381421659, 694757}, NULL) = 0
>> 16:14:19.694849 time(NULL)              = 1381421659
>> 16:14:19.694976 read(18, 0x7fcba7876a43, 5) = -1 EAGAIN (Resource temporarily unavailable)
>> 16:14:19.695091 epoll_wait(14, {{EPOLLOUT, {u32=2810463600, u64=140512665552240}}}, 10, 4294967295) = 1
>> 16:14:19.695201 gettimeofday({1381421659, 695230}, NULL) = 0
>> 16:14:19.695300 time(NULL)              = 1381421659
>> 16:14:19.695420 read(18, 0x7fcba7876a43, 5) = -1 EAGAIN (Resource temporarily unavailable)
>> 16:14:19.695555 epoll_wait(14,  <unfinished ...>
>>
>> dovecot -n output is:
>>
>> # 2.1.7: /etc/dovecot/dovecot.conf
>> # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.2 ext3
>> first_valid_uid = 8
>> last_valid_uid = 8
>> mail_access_groups = spamd-clients
>> mail_gid = mail
>> mail_location = mdbox:/var/spool/mail/%n/mdbox
>> mail_plugins = fts quota fts_lucene
>> mail_uid = mail
>> managesieve_notify_capability = mailto
>> managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave
>> namespace inbox {
>>   inbox = yes
>>   location = 
>>   mailbox Drafts {
>>     special_use = \Drafts
>>   }
>>   mailbox Sent {
>>     special_use = \Sent
>>   }
>>   mailbox "Sent Messages" {
>>     special_use = \Sent
>>   }
>>   mailbox Spam {
>>     special_use = \Junk
>>   }
>>   mailbox Trash {
>>     special_use = \Trash
>>   }
>>   prefix = 
>> }
>> passdb {
>>   args = scheme=SHA512-CRYPT username_format=%n /etc/dovecot/users
>>   driver = passwd-file
>> }
>> plugin {
>>   antispam_backend = pipe
>>   antispam_pipe_program = /usr/local/bin/spamc_wrapper
>>   antispam_pipe_program_notspam_args = -L;ham
>>   antispam_pipe_program_spam_args = -L;spam
>>   antispam_spam = Spam
>>   antispam_trash = Trash;Papierkorb
>>   fts = lucene
>>   fts_lucene = whitespace_chars=@.
>>   quota = dict:User quota::file:%h/quota
>>   quota_rule = *:storage=1G
>>   quota_rule2 = Trash:storage=+100M
>>   sieve = ~/.dovecot.sieve
>>   sieve_dir = ~/sieve
>> }
>> protocols = " imap lmtp sieve"
>> service auth {
>>   unix_listener auth-client {
>>     mode = 0600
>>     user = Debian-exim
>>   }
>> }
>> service lmtp {
>>   inet_listener lmtp {
>>     address = 127.0.0.1
>>     port = 2003
>>   }
>> }
>> service managesieve-login {
>>   inet_listener sieve {
>>     port = 4190
>>   }
>>   process_min_avail = 0
>>   service_count = 1
>> }
>> ssl_cert = </etc/dovecot/dovecot.pem
>> ssl_key = </etc/dovecot/private/dovecot.pem
>> userdb {
>>   args = username_format=%n /etc/dovecot/users
>>   driver = passwd-file
>>   override_fields = home=/var/spool/mail/%n
>> }
>> protocol lmtp {
>>   mail_plugins = fts quota fts_lucene sieve
>> }
>> protocol lda {
>>   mail_plugins = fts quota fts_lucene sieve
>> }
>> protocol imap {
>>   mail_max_userip_connections = 50
>>   mail_plugins = fts quota fts_lucene imap_quota antispam
>> }
>>
>>
>> Is this a bug in dovecot, or am I doing something wrong? Is there
>> something I can do to debug this further?
>>
>>
>> Best,
>> Nikolaus
>>
>> -- 
>> Encrypted emails preferred.
>> PGP fingerprint: 5B93 61F8 4EA2 E279 ABF6  02CF A9AD B7F8 AE4E 425C
>>
>>              »Time flies like an arrow, fruit flies like a Banana.«
> 
> 



Best Regards
MfG Robert Schetterer

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