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From: Thomas Gleixner <tglx@kernel.org>
To: Waiman Long <longman@redhat.com>, Tejun Heo <tj@kernel.org>, Johannes
 Weiner <hannes@cmpxchg.org>, Michal =?utf-8?Q?Koutn=C3=BD?=
 <mkoutny@suse.com>, Jonathan
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 Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, "K. Y.
 Srinivasan" <kys@microsoft.com>, Haiyang Zhang <haiyangz@microsoft.com>,
 Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>, Long Li
 <longli@microsoft.com>, Guenter Roeck <linux@roeck-us.net>, Frederic
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 Anna-Maria Behnsen <anna-maria@linutronix.de>, Ingo Molnar
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 <mgorman@suse.de>, Valentin Schneider <vschneid@redhat.com>, K Prateek
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 Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>,
 Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>
Cc: cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 linux-hyperv@vger.kernel.org, linux-hwmon@vger.kernel.org,
 rcu@vger.kernel.org, netdev@vger.kernel.org,
 linux-kselftest@vger.kernel.org, Costa Shulyupin <cshulyup@redhat.com>,
 Qiliang Yuan <realwujing@gmail.com>, Waiman Long <longman@redhat.com>
Subject: Re: [PATCH 11/23] hrtimer: Use RCU to protect access of
 HK_TYPE_TIMER cpumask
In-Reply-To: <20260421030351.281436-12-longman@redhat.com>
References: <20260421030351.281436-1-longman@redhat.com>
 <20260421030351.281436-12-longman@redhat.com>
Date: Tue, 21 Apr 2026 10:59:24 +0200
Message-ID: <87tst4bser.ffs@tglx>
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On Mon, Apr 20 2026 at 23:03, Waiman Long wrote:
> As HK_TYPE_TIMER cpumask is going to be changeable at run time, use

As the ...

> RCU to protect access to the cpumask.
>
> The access of HK_TYPE_TIMER cpumask within hrtimers_cpu_dying() is
> protected as interrupt is disabled and all the other CPUs are stopped

interrupts are disabled

> when this function is invoked as part of the CPU tear down process.