Re: Handles the masked signal when the thread exits

[Gibeom Gwon <gb.gwon@stackframe.dev>]

On 11/19/21 03:31, Florian Weimer wrote:
> * Gibeom Gwon:
> 
>> On 11/19/21 03:19, Florian Weimer wrote:
>>> * Gibeom Gwon:
>>>
>>>> On 11/19/21 03:08, Florian Weimer wrote:
>>>>> * Gibeom Gwon:
>>>>>
>>>>>> I am experiencing strange(unintended?) behavior when using pthread
>>>>>> with signals. If I set the signal mask with pthread_sigmask() in the
>>>>>> thread function and the process has pending signal when thread is
>>>>>> exiting, signal handler executed in thread.
>>>>>>
>>>>>> It looks like glibc restores original signal mask at the end of the
>>>>>> thread. So I suspect this eventually triggers masked signal
>>>>>> handler. But I'm not sure it is intended or not.
>>>>> Which glibc version are you using?
>>>
>>>> Ah, I forgot to write the version. I'm using 2.33 and linux
>>>> distribution is Arch Linux.
>>> We had some issues with signals and thread exit in 2.34, but they
>>> are
>>> exclusive to that release and cannot happen in 2.33.  I can't reproduce
>>> the behavior you see with upstream 2.33, either.
>>> What's your kernel version?  I've tried 5.14.13 and 5.14.17.
>>> Thanks,
>>> Florian
>>>
>>
>> Kernel version is 5.15.2.
>>
>> Well, I accidently dropped sleep.c code sample. Here are the code
>> samples again. Sorry to bother you.
> 
> Ah, now the test makes a little bit more sense.  But I still get the
> expected output:
> 
> main thread: 140317152449984
> child thread: 140317150295616
> worker...
> worker...
> worker...
> worker...
> worker...
> worker...
> worker...
> worker...
> worker...
> worker...
> thread close
> sigchld: 140317152449984
> 
> So the signal gets delivered on the main thread, as expected.
> 
> Thanks,
> Florian
> 

I hit Ctrl+C in the middle of running signal program. You can see
^C and sigint:.. printed in my result.

Regards,
Gibeom Gwon