From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Mon, 4 Apr 2022 14:40:14 +0200 (CEST)
From: Richard Weinberger <richard@nod.at>
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Subject: Re: [PATCH] Alchemy: Fix rt_task_unblock() for RT_MUTEX
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: xenomai <xenomai@xenomai.org>

----- Urspr=C3=BCngliche Mail -----
> Von: "Jan Kiszka" <jan.kiszka@siemens.com>
>> Uff yes. Just tried building with --with-core=3Dmercury and it failed. ;=
-\
>>=20
>> So, when mercury is enabled, alchemy will use NPTL.
>> This means rt_task_unblock() cannot work on mercury because
>> pthread_mutex_lock() will not return EINTR either.
>>=20
>> Fixing the build for mercury should be easy by adding an ifdef
>> CONFIG_XENO_MERCURY.
>> But I'm not sure how to fix unblocking for the mercury case.
>=20
> Either by ignoring that case on mercury (it has not predecessor in
> Xenomai 2, and it can't be fixed via posix means) or by redefining the
> behavior for everyone, i.e. by exempting rt_mutex_acquire* from
> rt_task_unblock.

I'd strongly vote for option #1. The application I work an cleans
up deadlocks with rt_task_unblock().
This seems to work quite well on Xenomai 2.

Thanks,
//richard