 22 Mar 2022, Konstantin Olchanski, Bug Fix, fix for event buffer corruption in bm_flush_cache()
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multithreaded frontends have an unusual event buffer corruption if the write
cache is enabled. For a long time now I had to disable the write cache on
all multithreaded frontends in alpha-g, I was hitting this bug quite often.
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 22 Mar 2022, Stefan Ritt, Bug Fix, fix for event buffer corruption in bm_flush_cache()
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Thanks Konstantin for your detailed description.
I wonder why we never saw this problem at PSI. Here is the reason: In multil-threaded environments, we never call bm_send_event() directly
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23 Mar 2022, Ivo Schulthess, Bug Fix, fix for event buffer corruption in bm_flush_cache()
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Thanks for the investigation. Back in 2020, we had some issues of losing data between the system buffer and the logger writing them to disk (https://daq00.triumf.ca/elog-midas/Midas/1966).
This was polled equipment but we had a multithreaded FE running at the same time. Could this be related to the same problem?
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23 Mar 2022, Konstantin Olchanski, Bug Fix, mhttpd ipv6 bind should be fixed now
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> Something changed after my initial implementation of ipv6 in mhttpd
> and listening to ipv6 http/https connections was broken.
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23 Mar 2022, Konstantin Olchanski, Bug Fix, fix for event buffer corruption in bm_flush_cache()
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I confirm, there is no problem in single-threaded programs, and
there is no problem if all bm_send_event() and bm_flush_cache() are called
from the same thread.
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23 Mar 2022, Konstantin Olchanski, Bug Fix, mhttpd bug fixed
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the mhttpd bug should be fixed now (branch feature/buffer_mutex).
simplest way to reproduce:
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24 Mar 2022, Stefan Ritt, Bug Fix, mhttpd bug fixed
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> 1st wget stops (by ctrl-C), socket is closed, mongoose frees it's mg_connection object
> (corresponding worker is still labouring, hmm... actually sleeping, and now has a stale nc pointer)
>
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24 Mar 2022, Stefan Ritt, Bug Fix, fix for event buffer corruption in bm_flush_cache()
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> > ... instead of struggling with all your locks.
>
> it is better to have midas fully thread safe. ODB has been so for a long time,
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24 Mar 2022, Konstantin Olchanski, Bug Fix, mhttpd bug fixed
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> > 1st wget stops (by ctrl-C), socket is closed, mongoose frees it's mg_connection object
> > (corresponding worker is still labouring, hmm... actually sleeping, and now has a stale nc pointer)
> >
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24 Mar 2022, Konstantin Olchanski, Bug Fix, fix for event buffer corruption in bm_flush_cache()
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> Thanks for the investigation. Back in 2020, we had some issues
> of losing data between the system buffer and the logger writing them
> to disk (https://daq00.triumf.ca/elog-midas/Midas/1966). This was polled equipment
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24 Mar 2022, Stefan Ritt, Bug Fix, mhttpd bug fixed
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I see, now I understand.
As for the browser cache problem: This Chrome extension is your friend:
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24 Mar 2022, Konstantin Olchanski, Bug Fix, mhttpd bug fixed
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> As for the browser cache problem: This Chrome extension is your friend ...
for google chrome, it is easy, open the javascript debugger (left-click "inspect"),
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29 Mar 2022, Konstantin Olchanski, Bug Fix, mdump can read lz4 and bz2 files now
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I converted mdump file i/o from older mdsupport library to newer midasio library
and it can now read .mid, .mid.gz, .mid.lz4 and .mid.bz2 files. Output should be
identical to what it printed before, if you see any differences, please report
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30 Mar 2022, Konstantin Olchanski, Bug Fix, erroneous removal of odb clients, fixed
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commit https://bitbucket.org/tmidas/midas/commits/b1fe21445109774be3f059c2124727b414abf835
made on 2022-02-21 fixed a serious bug in ODB.
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31 Mar 2022, Konstantin Olchanski, Bug Fix, "run stop" trouble in mlogger, fixed
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while debugging something else, I ran into a bit of trouble in mlogger.
I set the mlogger event limit to 100, and after reaching 100 events, mlogger
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24 Apr 2022, Konstantin Olchanski, Bug Fix, mserver buffer overrun and crash
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There is a memory allocation bug in the mserver.
ALIGN8() was missing when receiving events from the event socket and data buffer
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04 May 2022, Konstantin Olchanski, Bug Fix, mysql history update
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the code for writing midas history to mysql has been updated to work against
MYSQL 8.0.23 (CERN ALPHA-2):
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16 May 2022, Konstantin Olchanski, Bug Fix, mserver buffer overrun and crash
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> There is a memory allocation bug in the mserver.
Fix for this problem introduced a new problem, an infinite loop in bm_flush_cache,
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19 Aug 2022, Konstantin Olchanski, Bug Fix, "Detected duplicate or non-monotonous data" in history files
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serious (but rare) bug was fixed in the history reader. unlucky experiment would see
errors about "Detected duplicate or non-monotonous data" in some history file, fixed by
removing/renaming the offending file. (reported by MEG experiment)
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23 Aug 2022, Konstantin Olchanski, Bug Fix, "Detected duplicate or non-monotonous data" in history files
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> serious (but rare) bug was fixed in the history reader.
previous fix was incomplete. please update to git commit
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