Re: [TCLCORE] PURIFY and unloading extensions issue (?)

[Neophytos D. <neo...@gm...>]

hmm, I disabled all above extensions and it still occurs, which reminded me
I also use Thread package 3.0b2 and some preliminary investigation seems to
show that it only happens when Thread package is loaded (3.0b2)

more tomorrow and again sorry for wasting your time

- Neophytos


On Mon, Jul 29, 2024 at 7:22 AM Neophytos Demetriou <neo...@gm...>
wrote:

> Hi Sergey,
>
> Thanks for your message. Answers below.
>
> did you test it before or after [96910cd8822ffb8f]
>> <https://core.tcl-lang.org/tcl/info/96910cd8822ffb8f>? Just to ensure it
>> is still acute...
>>
>
> It was with tcl 9.0b2, so before that change.
>
>
>> The whole "unload" thing was initially introduced by Nathan in
>> [3b0e92b198b86975] <https://core.tcl-lang.org/tcl/info/3b0e92b198b86975>,
>> however it seemed to have some issues (like [34870ab5756911d1]
>> <https://core.tcl-lang.org/tcl/info/34870ab5756911d1> or
>> [ae09f6b190ceec31] <https://core.tcl-lang.org/tcl/info/ae09f6b190ceec31>),
>> which I tried to fix in the last time as good as I was able to do that.
>>
>
> I cannot tell if it is relevant or not. It does not look like it.
>
>
>> Which versions (and platforms) are affected or do you mean exactly here?
>> Is it stock tcl or some application of you, that uses Tcl as a subsystem
>> (in particular, it is Tcl_Main* or your own main)?
>>
>
> It was a tcl file that loaded twebserver in the main thread and
> twebserver, tjson and thtml in the spawn twebserver threads. All of these
> extensions were using Tcl_CreateThreadExitHandler in their initialization
> function. They did not have to but I did not notice that was the case
> before this issue. Changing them all to use CreateExitHandler seems to have
> resolved the issue.
>
> I will investigate further tomorrow and report back but my guess is that
> there is a TCL_TSD_INIT used somewhere when the thread exit handler runs
> that causes this issue during unload.
>
> Regards,
> Neophytos
>
> PS. My apologies but I have to run right now. I will check further
> tomorrow and report back.
>
> Regards,
>> Sergey.
>>
>> 29.07.2024 10:29, Neophytos Demetriou wrote:
>>
>> Hi,
>>
>> When the PURIFY flag is used Tcl_Exit calls Tcl_Finalize that in turn
>> calls TclFinalizeSynchronization, which sets tsdGlobal.key to NULL via
>> TclFinalizeThreadStorage.
>>
>> Then, when it afterwards tries to unload extensions, it attempts to use
>> the TSD (thread-specific data) again and because tsdGlobal.key is NULL, the
>> AddressSanitizer complains about a NULL pthread key.
>>
>> I was not able to track where the TSD is used during unloading or if this
>> is an issue with the extensions being used and whether they have to unload
>> in a specific way. As a consequence I stopped using the PURIFY flag but if
>> anyone has any suggestions, please let us know.
>>
>> Kind regards,
>> Neophytos
>>
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