linux-kernel - Re: [PATCH] sched/deadline: Fix imbalanced task reference

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Message-ID: <ZrM3rZFGg_nPEjjV@jlelli-thinkpadt14gen4.remote.csb>
Date: Wed, 7 Aug 2024 11:00:29 +0200
From: Juri Lelli <juri.lelli@...hat.com>
To: Zhang Qiao <zhangqiao22@...wei.com>
Cc: Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>,
	linux-kernel@...r.kernel.org, Wander Costa <wcosta@...hat.com>
Subject: Re: [PATCH] sched/deadline: Fix imbalanced task reference

Hi,

On 07/08/24 16:30, Zhang Qiao wrote:
> When starting a deadline inactive_timer, the task_struct refs will
> be incremented only if dl_server is not set. But when canceling the
> inactive_timer, the task refs will be decremented whether dl_server is
> set or not, leading to a task reference imbalance issue.
> 
> This patch fixes the imbalanced reference by adding a '!dl_server()'
> checker before calling put_task_struct().
> 
> Fixes: 63ba8422f876 ("sched/deadline: Introduce deadline servers")
> Signed-off-by: Zhang Qiao <zhangqiao22@...wei.com>

Isn't this equivalent to Wander's patch below?

https://lore.kernel.org/lkml/20240724142253.27145-3-wander@redhat.com/

Thanks,
Juri