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Date:   Thu, 16 Jul 2020 16:25:37 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Uladzislau Rezki <urezki@gmail.com>
Cc:     Joel Fernandes <joel@joelfernandes.org>,
        LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Theodore Y . Ts'o" <tytso@mit.edu>,
        Matthew Wilcox <willy@infradead.org>,
        Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: Re: [PATCH 1/1] rcu/tree: Drop the lock before entering to page
 allocator
Message-ID: <20200716142537.ecp4icsq7kg6qhdx@linutronix.de>
References: <20200715183537.4010-1-urezki@gmail.com>
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On 2020-07-16 11:19:13 [+0200], Uladzislau Rezki wrote:
> Sebastian, could you please confirm that if that patch that is in
> question fixes it?
> 
> It would be appreciated!

So that preempt disable should in terms any warnings. However I don't
think that it is strictly needed and from scheduling point of view you
forbid a CPU migration which might be good otherwise.
Also if interrupts and everything is enabled then someone else might
invoke kfree_rcu() from BH context for instance.

Sebastian