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From: Andrew Morton <akpm@linux-foundation.org>
To: Wander Lairson Costa <wander@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andy Lutomirski <luto@kernel.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"Liam R. Howlett" <Liam.Howlett@Oracle.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Andrei Vagin <avagin@gmail.com>,
	linux-kernel@vger.kernel.org (open list),
	Hu Chunyu <chuhu@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>,
	Paul McKenney <paulmck@kernel.org>
Subject: Re: [PATCH v4] kernel/fork: beware of __put_task_struct calling context
Date: Mon, 6 Feb 2023 17:09:27 -0800	[thread overview]
Message-ID: <20230206170927.9d5afee653dfa0738983dbfa@linux-foundation.org> (raw)
In-Reply-To: <20230206130449.41360-1-wander@redhat.com>

On Mon,  6 Feb 2023 10:04:47 -0300 Wander Lairson Costa <wander@redhat.com> wrote:

> Under PREEMPT_RT, __put_task_struct() indirectly acquires sleeping
> locks. Therefore, it can't be called from an non-preemptible context.

Well that's regrettable.  Especially if non-preempt kernels don't do
this.

Why does PREEMPT_RT do this and can it be fixed?

If it cannot be fixed then we should have a might_sleep() in
__put_task_struct() for all kernel configurations, along with an
apologetic comment explaining why.


  parent reply	other threads:[~2023-02-07  1:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-06 13:04 [PATCH v4] kernel/fork: beware of __put_task_struct calling context Wander Lairson Costa
2023-02-06 14:56 ` Sebastian Andrzej Siewior
2023-02-06 15:27   ` Oleg Nesterov
2023-02-06 16:04     ` Sebastian Andrzej Siewior
2023-02-06 16:27       ` Oleg Nesterov
2023-02-10 16:48         ` Sebastian Andrzej Siewior
2023-02-06 18:36       ` Wander Lairson Costa
2023-02-06 18:34     ` Wander Lairson Costa
2023-02-06 18:32   ` Wander Lairson Costa
2023-02-07  1:09 ` Andrew Morton [this message]
2023-02-07 15:26   ` Wander Lairson Costa
2023-02-10 17:08   ` Sebastian Andrzej Siewior

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