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Date: Wed, 9 Sep 2026 12:26:52 +0200
From: Niklas Cassel <cassel@kernel.org>
To: Rosen Penev <rosenp@gmail.com>
Cc: linux-ide@vger.kernel.org, Damien Le Moal <dlemoal@kernel.org>,
	Tejun Heo <tj@kernel.org>, Mans Rullgard <mans@mansr.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHv2] ata: sata_dwc_460ex: fix data race on
 hsdev->sactive_issued in interrupt handler
Message-ID: <aqE0bJHPwF9Rer_E@ryzen>
References: <20260908214212.597139-1-rosenp@gmail.com>
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In-Reply-To: <20260908214212.597139-1-rosenp@gmail.com>

On Tue, Sep 08, 2026 at 02:42:12PM -0700, Rosen Penev wrote:
> hsdev->sactive_issued is written locklessly in sata_dwc_isr() before
> acquiring host->lock, while sata_dwc_qc_complete() performs a
> read-modify-write on the same field under the lock.  This creates a
> data race that can corrupt NCQ tag tracking state.
> 
> Move the zero assignment inside the critical section so all accesses
> to sactive_issued are serialized by host->lock.
> 
> Fixes: 2d20da00c324b ("ata: sata_dwc_460ex: get rid of global data")

Fixes tag seems wrong.

Commit in fixes did:

-       host_pvt.sata_dwc_sactive_issued = 0;
+       hsdev->sactive_issued = 0;

        spin_lock_irqsave(&host->lock, flags);

ie. it simply did a rename, so sactive_issued was assigned to zero before
taking the lock, both before and after the commit in Fixes:.


Kind regards,
Niklas