[Nut-upsdev] [Nut-upsuser] Upssched 100% CPU after updating Debian 12
Jim Klimov
jimklimov+nut at gmail.com
Tue Jun 13 16:35:44 BST 2023
So... determining that FD is to be reaped proved hard. Internet lore
suggests fcntl() and poll() on the FD, but it just seems valid to them. The
errno is also usually not raised (once I saw a "111: Connection refused"
though).
So the best dumb idea so far is to bail out if we spent the whole loop (128
attempts) and only got zero-sized read replies and no errors.
https://github.com/networkupstools/nut/pull/1965
Jim
On Tue, Jun 13, 2023 at 4:06 PM Jim Klimov <jimklimov+nut at gmail.com> wrote:
> After launching the command several times, with debug (posted by new code
> in a new branch for the investigation) confirming that the same daemon
> handles operations from the new client instances, its strace now has
> numerous FDs to report after select() - so I guess it is a problem of
> detecting an exit of the counterpart.
>
>
>
> 0.000000 [D2] parse_at: is 'heartbeat at localhost' in AT command the
> 'heartbeat at localhost' we were launched to process?
> 0.000034 [D1] parse_at: 'heartbeat at localhost' in AT command
> matched the 'heartbeat at localhost' UPSNAME we were launched to process
> 0.000041 [D1] parse_at: processing CANCEL-TIMER
> 0.000054 [D2] parse_at: is 'heartbeat at localhost' in AT command the
> 'heartbeat at localhost' we were launched to process?
> 0.000057 [D1] parse_at: 'heartbeat at localhost' in AT command
> matched the 'heartbeat at localhost' UPSNAME we were launched to process
> 0.000060 [D1] parse_at: processing START-TIMER
> 0.000151 [D1] Keeping stderr open due to debug verbosity 8
> 0.000195 Timer daemon started
> 0.000204 [D2] Timer daemon waiting for connections on pipefd 10
> 0.250325 [D3] new connection on fd 7
> 0.250377 New timer: heartbeat-failure-timer (660 seconds)
> 0.250423 [D1] Exiting upssched (CLI process)
>
> 0.000000 [D2] parse_at: is 'heartbeat at localhost' in AT command the
> 'heartbeat at localhost' we were launched to process?
> 0.000039 [D1] parse_at: 'heartbeat at localhost' in AT command
> matched the 'heartbeat at localhost' UPSNAME we were launched to process
> 0.000047 [D1] parse_at: processing CANCEL-TIMER
> 14.745773 [D3] new connection on fd 8
> 14.745829 Cancelling timer: heartbeat-failure-timer
> 0.000153 [D2] parse_at: is 'heartbeat at localhost' in AT command the
> 'heartbeat at localhost' we were launched to process?
> 0.000159 [D1] parse_at: 'heartbeat at localhost' in AT command
> matched the 'heartbeat at localhost' UPSNAME we were launched to process
> 0.000163 [D1] parse_at: processing START-TIMER
> 14.745890 [D3] new connection on fd 9
> 14.745969 New timer: heartbeat-failure-timer (660 seconds)
> 0.000293 [D1] Exiting upssched (CLI process)
>
> 0.000001 [D2] parse_at: is 'heartbeat at localhost' in AT command the
> 'heartbeat at localhost' we were launched to process?
> 0.000042 [D1] parse_at: 'heartbeat at localhost' in AT command
> matched the 'heartbeat at localhost' UPSNAME we were launched to process
> 0.000050 [D1] parse_at: processing CANCEL-TIMER
> 47.674032 [D3] new connection on fd 11
> 47.674160 Cancelling timer: heartbeat-failure-timer
> 0.000266 [D2] parse_at: is 'heartbeat at localhost' in AT command the
> 'heartbeat at localhost' we were launched to process?
> 0.000277 [D1] parse_at: 'heartbeat at localhost' in AT command
> matched the 'heartbeat at localhost' UPSNAME we were launched to process
> 0.000284 [D1] parse_at: processing START-TIMER
> 47.674235 [D3] new connection on fd 12
> 47.674388 New timer: heartbeat-failure-timer (660 seconds)
> 0.000487 [D1] Exiting upssched (CLI process)
>
> Note that `select` only lists remnants of "new connection" but not the
> FD#10 (pipefd):
>
> select(13, [7 8 9 10 11 12], NULL, NULL, {tv_sec=1, tv_usec=0}) = 5
> (in [7 8 9 11 12], left {tv_sec=0, tv_usec=999997})
>
> Jim
>
>
>
> On Tue, Jun 13, 2023 at 3:41 PM Jim Klimov <jimklimov+nut at gmail.com>
> wrote:
>
>> So, got some good news: I hear(*) I managed to reproduce the problem with
>> current NUT master and an adapted copy of your posted configs and script :D
>> Experimental debugging now sounds possible.
>>
>> (*) PC under the desk wails with all its cooling fans as soon as I
>> started the client which spawned a daemon and itself had exited:
>>
>> $ UPSNAME=heartbeat at localhost NOTIFYTYPE=ONBATT NUT_STATEPATH=/dev/shm
>> NUT_CONFPATH=`pwd`/tests/NIT/tmp/etc ./clients/upssched -DDDDDDDD
>> 0.000000 [D2] parse_at: is 'heartbeat at localhost' in AT command
>> the 'heartbeat at localhost' we were launched to process?
>> 0.000053 [D1] parse_at: 'heartbeat at localhost' in AT command
>> matched the 'heartbeat at localhost' UPSNAME we were launched to process
>> 0.000066 [D1] parse_at: processing CANCEL-TIMER
>> 0.000089 [D2] parse_at: is 'heartbeat at localhost' in AT command
>> the 'heartbeat at localhost' we were launched to process?
>> 0.000096 [D1] parse_at: 'heartbeat at localhost' in AT command
>> matched the 'heartbeat at localhost' UPSNAME we were launched to process
>> 0.000104 [D1] parse_at: processing START-TIMER
>>
>> $
>>
>> Jim
>>
>>
>> On Tue, Jun 13, 2023 at 1:58 PM Kari Lempiäinen <
>> kari.lempiainen at summerday.net> wrote:
>>
>>> Hi,
>>>
>>> Thanks Jim! Here is more system information from the commands you
>>> mentioned.
>>>
>>> Kari
>>>
>>> root at fricka:~# lsof -p 1716171
>>> lsof: WARNING: can't stat() fuse.gvfsd-fuse file system
>>> /run/user/1002/gvfs
>>> Output information may be incomplete.
>>> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE
>>> NAME
>>> upssched 1716171 root cwd DIR 8,2 4096 2 /
>>> upssched 1716171 root rtd DIR 8,2 4096 2 /
>>> upssched 1716171 root txt REG 8,2 39240 21762148
>>> /usr/sbin/upssched
>>> upssched 1716171 root mem REG 8,2 1922136 21764230
>>> /usr/lib/x86_64-linux-gnu/libc.so.6
>>> upssched 1716171 root mem REG 8,2 210968 21764476
>>> /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
>>> upssched 1716171 root 0u CHR 1,3 0t0 4
>>> /dev/null
>>> upssched 1716171 root 1u CHR 1,3 0t0 4
>>> /dev/null
>>> upssched 1716171 root 2u CHR 1,3 0t0 4
>>> /dev/null
>>> upssched 1716171 root 3u unix 0x00000000eeb52825 0t0 16427010
>>> type=DGRAM (CONNECTED)
>>> upssched 1716171 root 4r REG 8,2 545 39847858
>>> /etc/nut/upssched.conf
>>> upssched 1716171 root 5u unix 0x00000000a035b466 0t0 16426351
>>> type=STREAM (UNCONNECTED)
>>> upssched 1716171 root 6u unix 0x0000000050820b2b 0t0 16426352
>>> type=STREAM (UNCONNECTED)
>>> upssched 1716171 root 7u unix 0x00000000447aac0e 0t0 16424724
>>> /var/run/nut/upssched.pipe type=STREAM (CONNECTED)
>>> upssched 1716171 root 10u unix 0x00000000d7bd8088 0t0 16424722
>>> /var/run/nut/upssched.pipe type=STREAM (LISTEN)
>>>
>>>
>>> root at fricka:~# ps -ef|grep ups
>>> root 1425 1 0 Jun11 ? 00:00:00 sshd: /usr/sbin/sshd
>>> -D [listener] 0 of 10-100 startups
>>> root 1156722 1 0 00:00 ? 00:00:00 /usr/sbin/cupsd -l
>>> root 1156723 1 0 00:00 ? 00:00:00
>>> /usr/sbin/cups-browsed
>>> lp 1156748 1156722 0 00:00 ? 00:00:00
>>> /usr/lib/cups/notifier/dbus dbus://
>>> nut 1713117 1 0 14:30 ? 00:00:00 /lib/nut/dummy-ups
>>> -a heartbeat
>>> nut 1713154 1 0 14:30 ? 00:00:00 /lib/nut/usbhid-ups
>>> -a eaton5s
>>> nut 1713155 1 0 14:30 ? 00:00:00 /lib/nut/upsd -F
>>> root 1713156 1 0 14:30 ? 00:00:00 /lib/nut/upsmon -F
>>> root 1713157 1713156 0 14:30 ? 00:00:00 /lib/nut/upsmon -F
>>> root 1716171 1 99 14:35 ? 00:05:10 /sbin/upssched UPS
>>> heartbeat at localhost: On battery.
>>> root 1719510 1550505 0 14:40 pts/2 00:00:00 grep ups
>>>
>>>
>>>
>>>
>>> root at fricka:~# fuser /var/run/nut/upssched.pipe
>>> /run/nut/upssched.pipe: 1716171
>>>
>>>
>>> root at fricka:/proc/1716171/fd# ls -la
>>> total 0
>>> dr-x------ 2 root root 0 Jun 13 14:36 .
>>> dr-xr-xr-x 9 root root 0 Jun 13 14:35 ..
>>> lrwx------ 1 root root 64 Jun 13 14:36 0 -> /dev/null
>>> lrwx------ 1 root root 64 Jun 13 14:36 1 -> /dev/null
>>> lrwx------ 1 root root 64 Jun 13 14:36 10 -> 'socket:[16424722]'
>>> lrwx------ 1 root root 64 Jun 13 14:36 2 -> /dev/null
>>> lrwx------ 1 root root 64 Jun 13 14:36 3 -> 'socket:[16427010]'
>>> lr-x------ 1 root root 64 Jun 13 14:36 4 -> /etc/nut/upssched.conf
>>> lrwx------ 1 root root 64 Jun 13 14:36 5 -> 'socket:[16426351]'
>>> lrwx------ 1 root root 64 Jun 13 14:36 6 -> 'socket:[16426352]'
>>> lrwx------ 1 root root 64 Jun 13 14:36 7 -> 'socket:[16424724]'
>>>
>>>
>>>
>>> ------------------------------
>>> *From:* Jim Klimov <jimklimov+nut at gmail.com>
>>> *Sent:* Tuesday, June 13, 2023 14:17
>>> *To:* Kari Lempiäinen <kari.lempiainen at summerday.net>
>>> *Cc:* Arnaud Quette via Nut-upsuser <nut-upsuser at alioth-lists.debian.net>;
>>> nut-upsdev <nut-upsdev at alioth-lists.debian.net>; Dimitris Economou <
>>> dimitris.s.economou at gmail.com>
>>> *Subject:* Re: [Nut-upsuser] Upssched 100% CPU after updating Debian 12
>>>
>>> FWIW, cross-posted the issue to NUT GitHub tracker:
>>> https://github.com/networkupstools/nut/issues/1964
>>>
>>> Jim
>>>
>>
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