Re: Handles the masked signal when the thread exits

[Florian Weimer <fweimer@redhat.com>]

* 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