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From: Florian Weimer <fweimer@redhat.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH v2 05/19] nptl: Move setxid flag out of cancelhandling
Date: Thu, 26 Aug 2021 13:34:27 +0200	[thread overview]
Message-ID: <87tujc783g.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20210823195047.543237-6-adhemerval.zanella@linaro.org> (Adhemerval Zanella's message of "Mon, 23 Aug 2021 16:50:33 -0300")

* Adhemerval Zanella:

> Now that the thread state is tracked by 'joinstate' field, there is no
> need to keep the setxid flag within the 'cancelhandling'.  It simplifies
> the atomic code to set and reset it (since there is no need to handle
> the thread state concurrent update).

Some of this functionality reimplements the tidlock.

There is some functionality around thread creation, but I do not know if
the synchronization is entirely correct.  This makes it rather difficult
to review changes.

It's also not clear to me if we need to do anything to prevent early
setxid calls:

>  	  /* Don't allow setxid until cloned.  */

I suspect this should just look at the TID instead.  We create the
thread with all signals blocked, so once there is a TID (and the thread
has not exited), it is safe to send the signal.

> diff --git a/nptl/descr.h b/nptl/descr.h
> index 4b2db6edab..563b152bff 100644
> --- a/nptl/descr.h
> +++ b/nptl/descr.h

> +  /* Indicate whether thread is supposed to change XID.  */
> +  int setxid_flag;

This should document the possible values.

Thanks,
Florian


  reply	other threads:[~2021-08-26 11:34 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-23 19:50 [PATCH v2 00/19] Fix various NPTL synchronization issues Adhemerval Zanella
2021-08-23 19:50 ` [PATCH v2 01/19] nptl: Fix tst-cancel7 and tst-cancelx7 race condition (BZ #14232) Adhemerval Zanella
2021-08-26  9:33   ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 02/19] nptl: Set cancellation type and state on pthread_exit Adhemerval Zanella
2021-08-26  9:38   ` Florian Weimer
2021-08-26  9:42     ` Florian Weimer
2021-08-26 11:56       ` Adhemerval Zanella
2021-08-26 11:52     ` Adhemerval Zanella
2021-08-26 12:08       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 03/19] nptl: Handle robust PI mutexes for !__ASSUME_SET_ROBUST_LIST Adhemerval Zanella
2021-08-26  9:42   ` Florian Weimer
2021-08-26 12:14     ` Adhemerval Zanella
2021-08-23 19:50 ` [PATCH v2 04/19] nptl: Do not use pthread set_tid_address as state synchronization (BZ #19951) Adhemerval Zanella
2021-08-26 10:41   ` Florian Weimer
2021-08-26 14:58     ` Adhemerval Zanella
2021-08-26 15:06       ` Florian Weimer
2021-08-26 16:16         ` Adhemerval Zanella
2021-08-30 10:42           ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 05/19] nptl: Move setxid flag out of cancelhandling Adhemerval Zanella
2021-08-26 11:34   ` Florian Weimer [this message]
2021-08-26 15:11     ` Adhemerval Zanella
2021-08-26 15:21       ` Florian Weimer
2021-08-26 16:39         ` Adhemerval Zanella
2021-08-30 11:27           ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 06/19] nptl: Replace struct thread cancelhandling field Adhemerval Zanella
2021-08-26 14:34   ` Florian Weimer
2021-08-26 16:48     ` Adhemerval Zanella
2021-08-30 10:36       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 07/19] support: Add support_wait_for_thread_exit Adhemerval Zanella
2021-08-26  9:31   ` Florian Weimer
2021-08-26 16:49     ` Adhemerval Zanella
2021-08-30 11:46       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 08/19] nptl: pthread_kill, pthread_cancel should fail after exit (bug 19193) Adhemerval Zanella
2021-08-26 10:03   ` Florian Weimer
2021-08-26 16:49     ` Adhemerval Zanella
2021-08-23 19:50 ` [PATCH v2 09/19] nptl: Fix race between pthread_kill and thread exit (bug 12889) Adhemerval Zanella
2021-08-26 14:23   ` Florian Weimer
2021-08-26 17:06     ` Adhemerval Zanella
2021-08-30  9:25       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 10/19] nptl: Use tidlock when accessing TID on pthread_getaffinity_np Adhemerval Zanella
2021-08-26 14:24   ` Florian Weimer
2021-08-26 17:29     ` Adhemerval Zanella
2021-08-30  9:30       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 11/19] nptl: Use tidlock when accessing TID on pthread_setaffinity Adhemerval Zanella
2021-08-26 14:25   ` Florian Weimer
2021-08-26 17:31     ` Adhemerval Zanella
2021-08-23 19:50 ` [PATCH v2 12/19] nptl: Use tidlock when accessing TID on pthread_getcpuclockid Adhemerval Zanella
2021-08-26 14:27   ` Florian Weimer
2021-08-26 17:41     ` Adhemerval Zanella
2021-08-30  9:34       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 13/19] nptl: Use tidlock when accessing TID on pthread_getschedparam Adhemerval Zanella
2021-08-26 15:00   ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 14/19] nptl: Use tidlock when accessing TID on pthread_setschedparam Adhemerval Zanella
2021-08-26 14:35   ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 15/19] nptl: Use tidlock when accessing TID on pthread_getname_np Adhemerval Zanella
2021-08-26 14:38   ` Florian Weimer
2021-08-26 17:45     ` Adhemerval Zanella
2021-08-30  9:37       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 16/19] nptl: Use tidlock when accessing TID on pthread_setname_np Adhemerval Zanella
2021-08-23 19:50 ` [PATCH v2 17/19] nptl: Use tidlock when accessing TID on pthread_sigqueue Adhemerval Zanella
2021-08-26 14:43   ` Florian Weimer
2021-08-26 17:49     ` Adhemerval Zanella
2021-08-30  9:26       ` Florian Weimer
2021-08-23 19:50 ` [PATCH v2 18/19] nptl: Use tidlock when accessing TID on pthread_setschedprio Adhemerval Zanella
2021-08-23 19:50 ` [PATCH v2 19/19] nptl: Remove INVALID_TD_P Adhemerval Zanella
2021-08-26  9:30   ` Florian Weimer
2021-08-26 14:47 ` [PATCH v2 00/19] Fix various NPTL synchronization issues Florian Weimer
2021-08-26 18:19   ` Adhemerval Zanella

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