On 05/01/2026 23:29, Andy Spiegl via dovecot wrote:
Dear dovecot team,
I believe I found a bug in dovecot on 32-bit systems.
Dovecot version:
1:2.4.1+dfsg1-6 (Architecture: i386)
Operating system:
Linux lar 6.13.7-64+ #1 SMP PREEMPT Fri Mar 21 08:33:47 MEZ 2025 x86_64
GNU/Linux
Distributor ID: Debian
Description: Debian GNU/Linux 13 (trixie)
Release: 13
Codename: trixie
* What led up to the situation?
Upgrade from 2.3.21.1 to 1:2.4.1
* What was the outcome of this action?
Logs are flooded with messages "Warning: Time moved forward"
* Problem Description:
The function io_loop_get_wait_time in ioloop.c contains the line:
ioloop->next_max_time.tv_sec = (1ULL << (TIME_T_MAX_BITS-1)) - 1;
On 32-bit systems TIME_T_MAX_BITS is 31 such that the result of this
calculation is 1073741823. Far from the
intended "infinity" and even before "now". This leads to problems in the
function io_loop_handle_timeouts_real:
the calculation of the time difference between now and next_max_time is then
something like -693628953 seconds
which confuses dovecot and floods the logs with these warnings:
Jan 02 17:43:43 lmtp(38364): Warning: Time moved forward 693630400.301863
seconds
Jan 02 17:43:43 lmtp(38364): Warning: Time moved forward 693630400.304144
seconds
Jan 02 17:45:43 lmtp(38364): Warning: Time moved forward 693630520.416053
seconds
* Possible solution/workaround ?
ioloop->next_max_time.tv_sec = INT_MAX;
Thanks for your consideration,
Andy
FWIW I've been observing the same issue on my 'lab' server since
installing Dovecot last month. (That system is also 32-bit Debian Trixie
and has the same version of Dovecot as above.) E.g.
2026-01-03T12:03:27.105027+13:00 lab dovecot: lmtp(5344): Warning: Time moved
forward 693653184.099749 seconds
2026-01-03T12:03:27.110568+13:00 lab dovecot: lmtp(5344): Warning: Time moved
forward 693653184.099842 seconds
I suspected it was a 32-bit issue, but hadn't got as far as trying to
diagnose. Nice work Andy! :-)
I also had this happen once:
2026-01-03T13:03:09.160310+13:00 lab dovecot: master: Panic: file time-util.h:
line 40 (timeval_add_usecs): assertion failed: (usecs >= 0)
2026-01-03T13:03:09.162076+13:00 lab dovecot: imap(5309): Panic: file
time-util.h: line 40 (timeval_add_usecs): assertion failed: (usecs >= 0)
2026-01-03T13:03:15.480689+13:00 lab dovecot: imap(5309): Error: Raw
backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 [unw_get_proc_name()
failed: -10] -> #3 i_panic[0xb7a8cf13] -> #4 [unw_get_proc_name() failed: -10]
-> #5 io_loop_handle_timeouts[0xb7b83eb0] -> #6
io_loop_handler_run_internal[0xb7b861d0] -> #7 io_loop_handler_run[0xb7b863b0]
-> #8 io_loop_run[0xb7b865c0] -> #9 master_service_run[0xb7ad02b0] -> #10
main[0x004158c0] -> #11 [unw_get_proc_name() failed: -10] -> #12
__libc_start_main[0xb7824d00] -> #13 _start[0x00416060]
2026-01-03T13:03:15.484895+13:00 lab dovecot: master: Error: Raw backtrace: #1
[unw_get_proc_name() failed: -10] -> #2 i_syslog_fatal_handler[0xb7c55960] ->
#3 [unw_get_proc_name() failed: -10] -> #4 i_panic[0xb7b7af13] -> #5
[unw_get_proc_name() failed: -10] -> #6 io_loop_handle_timeouts[0xb7c71eb0] ->
#7 io_loop_handler_run_internal[0xb7c741d0] -> #8
io_loop_handler_run[0xb7c743b0] -> #9 io_loop_run[0xb7c745c0] -> #10
master_service_run[0xb7bbe2b0] -> #11 main[0x00426d30] -> #12
[unw_get_proc_name() failed: -10] -> #13 __libc_start_main[0xb7912d00] -> #14
_start[0x00427d20]
2026-01-03T13:03:15.508827+13:00 lab dovecot: imap-login: Warning: Killed with
signal 15 (by pid=1 uid=0 code=kill)
2026-01-03T13:03:15.513404+13:00 lab dovecot: stats: Warning: Killed with
signal 15 (by pid=1 uid=0 code=kill)
2026-01-03T13:03:15.513766+13:00 lab dovecot: log(5302): Warning: Killed with
signal 15 (by pid=1 uid=0 code=kill)
2026-01-03T13:03:15.514010+13:00 lab dovecot: log(5302): Warning: Shutting
down logging for 'imap-login: ' with 1 clients
Given that this mentions time-util.h, I wonder if this issue is related?
Unfortunately I don't have a core file for this.
One thing I should point out is that this machine gets suspended
regularly, and when I want to test something I wake it up (wake-on-lan),
do stuff, then suspend it again.
Nick.
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