Thank you for your thorough report, we'll look into it. Aki
On 20.03.2018 16:56, Tomas Forsman wrote: > Hello. > > I seem to have found a race condition, when setting flags on multiple emails > rapidly. 5 commands including login to reproduce. Problem found using mutt in > real world usage. > > Seems to happen both with UID STORE 1:3 and UID STORE 1,2,3 .. > > I have tried with the following packages, with a minimized config in a > throwaway vm: > https://packages.debian.org/stretch/dovecot-core > Package: dovecot-core (1:2.2.27-3+deb9u2) > > https://packages.debian.org/stretch-backports/dovecot-core > Package: dovecot-core (1:2.2.34-2~bpo9+1) > > Also tested pristine: > https://dovecot.org/releases/2.3/dovecot-2.3.0.1.tar.gz > https://dovecot.org/releases/2.2/dovecot-2.2.34.tar.gz > https://dovecot.org/releases/2.2/dovecot-2.2.35.tar.gz > .. built on Debian9 with: > # apt-get build-dep dovecot-core > # bash configure --prefix=/scratch/dovecot-test > > Tried with both mailbox over NFS (backed by ext4), and also mailbox on ext4. > > On my test systems, I am only able to reproduce it with mbox_lazy_writes=no, > but with production settings on a Ubuntu 14.04 with 1:2.2.9-1ubuntu2.4 that > has > mbox_lazy_writes=yes it is still reproducable with mutt. > > I have found two different ways to reproduce it with netcat + cut'n'paste, > below is done with 2.2.34/35. > > All servers are VMs in Ganeti/kvm clusters (Debian hosts in one > cluster&organization, Ubuntu host in another cluster&organization). > > > Debian minimized config: >> doveconf -n > # 2.2.34 (874deae): /etc/dovecot/dovecot.conf > # Pigeonhole version 0.4.22 (22940fb7) > # OS: Linux 4.9.0-6-amd64 x86_64 Debian 9.4 > # Hostname: mail2-vm.cs.umu.se > auth_mechanisms = plain login > auth_verbose = yes > debug_log_path = syslog > info_log_path = syslog > mail_location = mbox:~/Mail:INBOX=/var/mail/%u > mail_privileged_group = mail > mbox_lazy_writes = no > namespace inbox { > inbox = yes > location = > prefix = > } > passdb { > driver = pam > } > protocols = imap > service auth { > client_limit = 2500 > unix_listener auth-client { > group = postfix > mode = 0660 > } > } > service imap-login { > inet_listener imap { > port = 143 > } > } > service imap { > executable = imap > } > ssl = no > syslog_facility = local1 > userdb { > driver = passwd > } > > > Attached is a mailbox that can be used to reproduce the problem, called > "error-box", anonymized with mbox-anonymize.pl. It was created by sending test > messages with mutt 1.7.2 through Dovecot/Postfix/Amavis. > > > > **** Method 1, with IDLE: > > Setup a local account, MY-USER / MY-PASSWORD (replace below). > >> mkdir Mail >> cp error-box Mail/error1 >> nc -v localhost 143 > Paste the following 3 lines in a go: > a0000 LOGIN "MY-USER" "MY-PASSWORD" > a0010 SELECT "error1" > a0020 IDLE > > then wait a second.. then paste the following 3 in a go: > DONE > a0030 UID STORE 1:3 +FLAGS (\Deleted) > a0040 EXPUNGE > > Notice that the results from UID STORE + EXPUNGE gives: > * 2 FETCH (UID 2 FLAGS (\Recent)) > * 3 FETCH (UID 3 FLAGS (\Recent)) > * 1 EXPUNGE > * 3 RECENT > a0030 OK Store completed (0.004 + 0.000 + 0.003 secs). > a0040 OK Expunge completed (0.004 + 0.000 + 0.003 secs). > > > Verify what's left in the mailbox with: > a0050 UID FETCH 1:4 FLAGS > * 1 FETCH (UID 2 FLAGS (\Recent)) > * 2 FETCH (UID 3 FLAGS (\Recent)) > * 3 FETCH (UID 4 FLAGS (\Recent)) > a0050 OK Fetch completed (0.001 + 0.000 secs). > > > Since 1 to 3 should be \Deleted and then EXPUNGEd, we should only have UID 4 > left, not uid 2-4 without Deleted flag. > > > Try same again, but with 1 inserted delay (use a new mailbox name for every > test, otherwise UID numbering will vary, indexes etc): >> cp error-box Mail/error2 >> nc -v localhost 143 > Paste the following 3 lines in a go: > a0000 LOGIN "MY-USER" "MY-PASSWORD" > a0010 SELECT "error2" > a0020 IDLE > > then wait a second.. then paste 1 line: > DONE > > then [newly introduced] wait a second.. then paste 2 lines: > a0030 UID STORE 1:3 +FLAGS (\Deleted) > a0040 EXPUNGE > > Notice that the results from UID STORE + EXPUNGE gives: > * 1 FETCH (UID 1 FLAGS (\Deleted \Recent)) > * 2 FETCH (UID 2 FLAGS (\Deleted \Recent)) > * 3 FETCH (UID 3 FLAGS (\Deleted \Recent)) > a0030 OK Store completed (0.003 + 0.000 + 0.002 secs). > * 3 EXPUNGE > * 2 EXPUNGE > * 1 EXPUNGE > * 1 RECENT > a0040 OK Expunge completed (0.003 + 0.000 + 0.002 secs). > > > Verify what's left in the mailbox with: > a0050 UID FETCH 1:4 FLAGS > * 1 FETCH (UID 4 FLAGS (\Recent)) > a0050 OK Fetch completed (0.001 + 0.000 secs). > > > So if I wait some between DONE and UID STORE, it seems to be ok. > > > > If I, in the problem-triggering method, change > a0030 UID STORE 1:3 +FLAGS (\Deleted) > a0040 EXPUNGE > to > a0030 UID STORE 1:3 +FLAGS (\Deleted) > a0035 UID FETCH 1:4 FLAGS > a0040 EXPUNGE > > The untagged responses become: > * 1 FETCH (UID 1 FLAGS (\Deleted \Recent)) > * 2 FETCH (UID 2 FLAGS (\Deleted \Recent)) > * 3 FETCH (UID 3 FLAGS (\Deleted \Recent)) > * 4 FETCH (UID 4 FLAGS (\Recent)) > * 2 FETCH (UID 2 FLAGS (\Recent)) > * 3 FETCH (UID 3 FLAGS (\Recent)) > * 1 EXPUNGE > * 3 RECENT > > > > > > Full transcript (in&out from screen) from first, failing, run: > > localhost [127.0.0.1] 143 (imap2) open > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE > AUTH=PLAIN AUTH=LOGIN] Dovecot (Debian) ready. > a0000 LOGIN "MY-USERNAME" "MY-PASSWORD" > a0010 SELECT "error1" > a0020 IDLE > a0000 OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE > IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT > MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS > LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN > CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY] Logged in > * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) > * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags > permitted. > * 4 EXISTS > * 4 RECENT > * OK [UNSEEN 1] First unseen. > * OK [UIDVALIDITY 1520944853] UIDs valid > * OK [UIDNEXT 5] Predicted next UID > a0010 OK [READ-WRITE] Select completed (0.003 + 0.000 + 0.004 secs). > + idling > DONE > a0030 UID STORE 1:3 +FLAGS (\Deleted) > a0040 EXPUNGE > a0020 OK Idle completed (7.805 + 7.804 + 7.804 secs). > * 2 FETCH (UID 2 FLAGS (\Recent)) > * 3 FETCH (UID 3 FLAGS (\Recent)) > * 1 EXPUNGE > * 3 RECENT > a0030 OK Store completed (0.004 + 0.000 + 0.003 secs). > a0040 OK Expunge completed (0.004 + 0.000 + 0.003 secs). > a0050 UID FETCH 1:4 FLAGS > * 1 FETCH (UID 2 FLAGS (\Recent)) > * 2 FETCH (UID 3 FLAGS (\Recent)) > * 3 FETCH (UID 4 FLAGS (\Recent)) > a0050 OK Fetch completed (0.001 + 0.000 secs). > > > > Full transcript (in&out from screen) from the second, slower, run: > > localhost [127.0.0.1] 143 (imap2) open > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE > AUTH=PLAIN AUTH=LOGIN] Dovecot (Debian) ready. > a0000 LOGIN "MY-USERNAME" "MY-PASSWORD" > a0010 SELECT "error2" > a0020 IDLE > a0000 OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE > IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT > MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS > LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN > CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY] Logged in > * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) > * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags > permitted. > * 4 EXISTS > * 4 RECENT > * OK [UNSEEN 1] First unseen. > * OK [UIDVALIDITY 1520944957] UIDs valid > * OK [UIDNEXT 5] Predicted next UID > a0010 OK [READ-WRITE] Select completed (0.003 + 0.000 + 0.004 secs). > + idling > DONE > a0020 OK Idle completed (2.830 + 2.829 + 2.829 secs). > a0030 UID STORE 1:3 +FLAGS (\Deleted) > a0040 EXPUNGE > * 1 FETCH (UID 1 FLAGS (\Deleted \Recent)) > * 2 FETCH (UID 2 FLAGS (\Deleted \Recent)) > * 3 FETCH (UID 3 FLAGS (\Deleted \Recent)) > a0030 OK Store completed (0.003 + 0.000 + 0.002 secs). > * 3 EXPUNGE > * 2 EXPUNGE > * 1 EXPUNGE > * 1 RECENT > a0040 OK Expunge completed (0.003 + 0.000 + 0.002 secs). > a0050 UID FETCH 1:4 FLAGS > * 1 FETCH (UID 4 FLAGS (\Recent)) > a0050 OK Fetch completed (0.001 + 0.000 secs). > > > > > Transcript from .muttdebug0 when using mutt 1.7.2 against the production > server > with NFS backed storage, marking message 1-3 for deletion and hitting $ for > sync. This is how the problem was first found. > > [2018-03-12 13:46:28] 5> a0020 IDLE^M > [2018-03-12 13:46:28] 5< + idling > ... > [2018-03-12 13:46:29] Marking 3 messages deleted... > [2018-03-12 13:46:29] Expunging messages from server... > [2018-03-12 13:46:29] 5> DONE^M > a0021 UID STORE 1:3 +FLAGS.SILENT (\Deleted)^M > a0022 EXPUNGE^M > [2018-03-12 13:46:29] 5< a0020 OK Idle completed (0.001 + 1.634 + 1.633 secs). > [2018-03-12 13:46:29] 5< * 2 FETCH (FLAGS (\Recent)) > [2018-03-12 13:46:29] Handling FETCH > [2018-03-12 13:46:29] FETCH response ignored for this message > [2018-03-12 13:46:29] 5< * 3 FETCH (FLAGS (\Recent)) > [2018-03-12 13:46:29] Handling FETCH > [2018-03-12 13:46:29] FETCH response ignored for this message > [2018-03-12 13:46:29] 5< * 1 EXPUNGE > [2018-03-12 13:46:29] Handling EXPUNGE > [2018-03-12 13:46:29] 5< * 3 RECENT > [2018-03-12 13:46:29] 5< a0021 OK Store completed (0.001 + 0.000 + 0.001 > secs). > [2018-03-12 13:46:29] 5< a0022 OK Expunge completed (0.001 + 0.000 secs). > [2018-03-12 13:46:29] IMAP queue drained > [2018-03-12 13:46:29] imap_cmd_finish: Expunging mailbox > > > > *** Method 2, without IDLE (seems to require that I fetch flags before the > wait/store) > > Copy'n'paste the following: > a0000 LOGIN "MY-USER" "MY-PASSWORD" > a0010 SELECT "error20" > a0015 FETCH 1:4 (UID FLAGS) > <wait a second, then paste the next two in one go> > a0020 UID STORE 1:3 +FLAGS (\Deleted) > a0025 EXPUNGE > > > Gives the following transcript: > > mail3-vm:~/Mail> nc -v localhost 143 > localhost [127.0.0.1] 143 (imap2) open > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE > AUTH=PLAIN AUTH=LOGIN] Dovecot ready. > a0000 LOGIN "MY-USER" "MY-PASSWORD" > a0010 SELECT "error20" > a0015 FETCH 1:4 (UID FLAGS) > a0000 OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE > IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT > MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS > LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN > CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY] Logged in > * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) > * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags > permitted. > * 4 EXISTS > * 4 RECENT > * OK [UNSEEN 1] First unseen. > * OK [UIDVALIDITY 1521552107] UIDs valid > * OK [UIDNEXT 5] Predicted next UID > a0010 OK [READ-WRITE] Select completed (0.001 + 0.000 + 0.001 secs). > * 1 FETCH (UID 1 FLAGS (\Recent)) > * 2 FETCH (UID 2 FLAGS (\Recent)) > * 3 FETCH (UID 3 FLAGS (\Recent)) > * 4 FETCH (UID 4 FLAGS (\Recent)) > a0015 OK Fetch completed (0.001 + 0.000 secs). > a0020 UID STORE 1:3 +FLAGS (\Deleted) > a0025 EXPUNGE > * 2 FETCH (UID 2 FLAGS (\Recent)) > * 3 FETCH (UID 3 FLAGS (\Recent)) > * 1 EXPUNGE > * 3 RECENT > a0020 OK Store completed (0.001 + 0.000 secs). > a0025 OK Expunge completed (0.001 + 0.000 secs). > > > > /Tomas
