From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH] nptl: Use SA_RESTART for SIGCANCEL handler
Date: Tue, 22 Jun 2021 15:50:41 -0300 [thread overview]
Message-ID: <8c620913-8cbe-b0ee-d232-f8c7a58263dd@linaro.org> (raw)
In-Reply-To: <87bl7xbvgs.fsf@oldenburg.str.redhat.com>
On 22/06/2021 15:33, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>> On 18/06/2021 08:38, Florian Weimer wrote:
>>> * Adhemerval Zanella via Libc-alpha:
>>>
>>>> The usage of signals to implementation pthread cancellation is an
>>>> implementation detail and should not be visible through cancellation
>>>> entrypoints.
>>>>
>>>> However now that pthread_cancel always send the SIGCANCEL, some
>>>> entrypoint might be interruptable and return EINTR to the caller
>>>> (for instance on sem_wait).
>>>>
>>>> Using SA_RESTART hides this, since the cancellation handler should
>>>> either act uppon cancellation (if asynchronous cancellation is enable)
>>>> or ignore the cancellation internal signal.
>>>
>>> I think this still needs a NEWS entry because there have been kernel
>>> bugs in this area (e.g. in CIFS).
>>
>> Ok, I have added the following on "Deprecated and removed features, and
>> other changes affecting compatibility"
>>
>> * The pthread cancellation handler is now setup with SA_RESTART. It should
>> not be visible to application since the cancellation handler should either
>> act uppon cancellation (if asynchronous cancellation is enabled) or
>> ignore the cancellation internal signal.
>
> The key change is: The cancellation signal is now sent in more cases,
> but this should be transparent to the application due to SA_RESTART.
I am not sure if we really need to describe this implementation detail
on a NEWS entry.
next prev parent reply other threads:[~2021-06-22 18:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 12:52 Adhemerval Zanella
2021-06-17 13:03 ` Andreas Schwab
2021-06-17 13:04 ` Adhemerval Zanella
2021-06-18 11:38 ` Florian Weimer
2021-06-22 18:30 ` Adhemerval Zanella
2021-06-22 18:33 ` Florian Weimer
2021-06-22 18:50 ` Adhemerval Zanella [this message]
2021-06-22 18:52 ` Florian Weimer
2021-06-22 19:50 ` Adhemerval Zanella
2021-06-22 19:51 ` Florian Weimer
2021-06-22 19:58 ` Adhemerval Zanella
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