linux-kernel - Re: [PATCH] workqueue: fix selection of wake_cpu in kick

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Message-ID: <ZiB9rYBu-0qjsCbF@slm.duckdns.org>
Date: Wed, 17 Apr 2024 15:55:57 -1000
From: Tejun Heo <tj@...nel.org>
To: Sven Schnelle <svens@...ux.ibm.com>
Cc: Lai Jiangshan <jiangshanlai@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] workqueue: fix selection of wake_cpu in kick_pool()

Hello,

On Wed, Apr 17, 2024 at 05:36:38PM +0200, Sven Schnelle wrote:
> > This generally seems like a good idea but isn't this still racy? The CPU may
> > go down between setting p->wake_cpu and wake_up_process().
> 
> Don't know without reading the source, but how does this code normally
> protect against that?

Probably by wrapping determining the wake_cpu and the wake_up inside
cpu_read_lock() section.

Thanks.

-- 
tejun