From: Jakub Kicinski <kuba@kernel.org>
To: Christian Eggers <ceggers@arri.de>
Cc: Vladimir Oltean <olteanv@gmail.com>,
Woojung Huh <woojung.huh@microchip.com>,
Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
Andrew Lunn <andrew@lunn.ch>,
Vivien Didelot <vivien.didelot@gmail.com>,
Florian Fainelli <f.fainelli@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
George McCollister <george.mccollister@gmail.com>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [net v4] net: dsa: microchip: fix race condition
Date: Mon, 12 Oct 2020 10:05:01 -0700 [thread overview]
Message-ID: <20201012100501.33a41d8a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20201012083942.12722-1-ceggers@arri.de>
On Mon, 12 Oct 2020 10:39:42 +0200 Christian Eggers wrote:
> Between queuing the delayed work and finishing the setup of the dsa
> ports, the process may sleep in request_module() (via
> phy_device_create()) and the queued work may be executed prior to the
> switch net devices being registered. In ksz_mib_read_work(), a NULL
> dereference will happen within netof_carrier_ok(dp->slave).
>
> Not queuing the delayed work in ksz_init_mib_timer() makes things even
> worse because the work will now be queued for immediate execution
> (instead of 2000 ms) in ksz_mac_link_down() via
> dsa_port_link_register_of().
>
> Solution:
> 1. Do not queue (only initialize) delayed work in ksz_init_mib_timer().
> 2. Only queue delayed work in ksz_mac_link_down() if init is completed.
> 3. Queue work once in ksz_switch_register(), after dsa_register_switch()
> has completed.
>
> Fixes: 7c6ff470aa86 ("net: dsa: microchip: add MIB counter reading support")
> Signed-off-by: Christian Eggers <ceggers@arri.de>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
> Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Now you went too far in the opposite direction, I never gave you my
explicit tag :) So I'll drop it.
Applied and queued for stable, thanks!
prev parent reply other threads:[~2020-10-12 17:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-12 8:39 [net v4] net: dsa: microchip: fix race condition Christian Eggers
2020-10-12 17:05 ` Jakub Kicinski [this message]
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