linux-kernel - Re: [PATCH] tick: use READ_ONCE() to read jiffies in concurrent environment

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Message-ID: <tencent_B8826A296A92B68C4B69570CADC250746A09@qq.com>
Date: Fri,  8 Mar 2024 16:46:59 +0800
From: linke li <lilinke99@...com>
To: tglx@...utronix.de
Cc: frederic@...nel.org,
	lilinke99@...com,
	linux-kernel@...r.kernel.org,
	mingo@...nel.org
Subject: Re: [PATCH] tick: use READ_ONCE() to read jiffies in concurrent environment

I am really sorry for making a confusing commit log.

>
> This patch finds nothing. Explain it correctly why it matters that the
> first read is not marked READ_ONCE(). Is this solving a correctness
> problem or are you adding it just to shut up the KCSAN warning?
>

The first read on jiffies is a racy read, and is expected to be racy.
So Mark data races to pwd->triggered as benign using READ_ONCE. This 
patch aiming at reducing the number of benign races reported by KCSAN
in order to focus future debugging effort on harmful races.