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From: Florian Weimer <fweimer@redhat.com>
To: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	 Michael Kerrisk <mtk.manpages@gmail.com>,
	Lukasz Majewski <lukma@denx.de>
Subject: Re: [PATCH 03/13] nptl: Remove clockwait_tid
Date: Mon, 14 Dec 2020 13:16:20 +0100	[thread overview]
Message-ID: <87v9d4d1m3.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <20201123195256.3336217-3-adhemerval.zanella@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Mon, 23 Nov 2020 16:52:46 -0300")

* Adhemerval Zanella via Libc-alpha:

> -static __always_inline int
> -futex_timed_wait_cancel64 (pid_t *tidp,  pid_t tid,
> -                           const struct __timespec64 *timeout, int private)
> -{
> -  int err = INTERNAL_SYSCALL_CANCEL (futex_time64, tidp,
> -                                     __lll_private_flag (FUTEX_WAIT, private),
> -                                     tid, timeout);

This uses FUTEX_WAIT.  But the replacement,
__futex_abstimed_wait_common64, uses FUTEX_WAIT_BITSET.  I do not think
this is correct because the kernel will use FUTEX_WAKE internally for
the pd->tid wakeup relied upon by pthread_join.

This seems to cause pthread_join regressions on some kernel versions.

We need to audit all callers of __futex_abstimed_wait64 if they are
actually compatible with FUTEX_WAIT_BITSET.

Thanks,
Florian
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  parent reply	other threads:[~2020-12-14 12:16 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-23 19:52 [PATCH 01/13] linux: Remove unused internal futex functions Adhemerval Zanella
2020-11-23 19:52 ` [PATCH 02/13] nptl: Remove futex_wait_cancelable Adhemerval Zanella
2020-11-24 18:01   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 03/13] nptl: Remove clockwait_tid Adhemerval Zanella
2020-11-24 18:13   ` Lukasz Majewski
2020-12-14 12:16   ` Florian Weimer [this message]
2020-12-14 12:47     ` Andreas Schwab
2020-12-14 13:11       ` Florian Weimer
2020-12-14 14:02         ` Florian Weimer
2020-12-14 12:52     ` Adhemerval Zanella
2020-11-23 19:52 ` [PATCH 04/13] linux: Extend __futex_abstimed_wait_cancelable64 comment Adhemerval Zanella
2020-11-24 18:16   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 05/13] linux: nptl: Consolidate __futex_abstimed_wait_{cancelable}64 Adhemerval Zanella
2020-11-24 18:19   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 06/13] linux: nptl: Remove _futex_clock_wait_bitset64 Adhemerval Zanella
2020-11-24 18:26   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 07/13] linux: nptl: Replace __futex_clocklock_wait64 with __futex_abstimed_wait64 Adhemerval Zanella
2020-11-24 21:28   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 08/13] linux: nptl: Replace lll_timedwait " Adhemerval Zanella
2020-11-24 21:29   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 09/13] linux: nptl: Replace lll_futex_{timed_}wait by futex-internal.h Adhemerval Zanella
2020-11-24 21:35   ` Lukasz Majewski
2020-11-25 15:32   ` Mike Crowe
2020-11-25 15:40     ` Adhemerval Zanella
2020-11-25 15:46       ` Mike Crowe
2020-11-25 17:19         ` Adhemerval Zanella
2020-11-25 17:37           ` Mike Crowe
2020-11-25 17:56             ` Adhemerval Zanella
2020-11-23 19:52 ` [PATCH 10/13] linux: nptl: Replace lll_futex_supported_clockid with futex-internal.h Adhemerval Zanella
2020-11-24 21:36   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH 11/13] nptl: Replace lll_futex_wake " Adhemerval Zanella
2020-11-24 21:38   ` Lukasz Majewski
2020-11-23 19:52 ` [PATCH v2 12/13] nptl: Return EINVAL for pthread_mutex_clocklock/PI with CLOCK_MONOTONIC [BZ #26801] Adhemerval Zanella
2020-11-24 21:43   ` Lukasz Majewski
2020-11-24 21:49   ` Lukasz Majewski
2020-11-27 17:39     ` Adhemerval Zanella
2020-11-23 19:52 ` [PATCH 13/13] linux: Return EINVAL for invalid clock for pthread_clockjoin_np Adhemerval Zanella
2020-11-24 21:48   ` Lukasz Majewski
2020-11-24 22:58     ` Lukasz Majewski
2020-11-24 17:51 ` [PATCH 01/13] linux: Remove unused internal futex functions Lukasz Majewski

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