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	Fri, 17 Apr 2026 17:46:36 +0000
Date: Fri, 17 Apr 2026 10:46:29 -0700
From: Breno Leitao <leitao@debian.org>
To: Daniel Golle <daniel@makrotopia.org>
Cc: "Chester A. Unal" <chester.a.unal@arinc9.com>, 
	Andrew Lunn <andrew@lunn.ch>, Vladimir Oltean <olteanv@gmail.com>, 
	"David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, 
	Matthias Brugger <matthias.bgg@gmail.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, Russell King <linux@armlinux.org.uk>, 
	Christian Marangi <ansuelsmth@gmail.com>, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, 
	Frank Wunderlich <frank-w@public-files.de>, John Crispin <john@phrozen.org>
Subject: Re: [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in
 atomic context
Message-ID: <aeJjcoHyezEgUG_Q@gmail.com>
References: <79dc0ec5b6be698b14cb66339d6f63033ca2934a.1776397542.git.daniel@makrotopia.org>
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In-Reply-To: <79dc0ec5b6be698b14cb66339d6f63033ca2934a.1776397542.git.daniel@makrotopia.org>
X-Debian-User: leitao

On Fri, Apr 17, 2026 at 04:55:57AM +0100, Daniel Golle wrote:
> @@ -3404,6 +3449,9 @@ EXPORT_SYMBOL_GPL(mt7530_probe_common);
>  void
>  mt7530_remove_common(struct mt7530_priv *priv)
>  {
> +	if (priv->bus)
> +		cancel_delayed_work_sync(&priv->stats_work);
> +

Shouldn't you cancel the work later, after dsa_unregister_switch()?

I am wondering if the following race cannot happen:

 mt7530_remove_common()                  someone reading /proc/net/dev
    cancel_delayed_work_sync()
      /* returns: work neither pending
         nor executing - true at this
         instant */
                                          mt7530_get_stats64()
                                            mod_delayed_work(...)
                                            /* work is queued again */
    dsa_unregister_switch()
    return