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From: Vladimir Oltean <olteanv@gmail.com>
To: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Cc: p.rosenberger@kunbus.com, woojung.huh@microchip.com,
	UNGLinuxDriver@microchip.com, andrew@lunn.ch,
	vivien.didelot@gmail.com, f.fainelli@gmail.com,
	davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] Fix for KSZ DSA switch shutdown
Date: Thu, 9 Sep 2021 13:14:51 +0300	[thread overview]
Message-ID: <20210909101451.jhfk45gitpxzblap@skbuf> (raw)
In-Reply-To: <20210909095324.12978-1-LinoSanfilippo@gmx.de>

On Thu, Sep 09, 2021 at 11:53:21AM +0200, Lino Sanfilippo wrote:
> This patch series fixes a system hang I got each time i tried to shutdown
> or reboot a system that uses a KSZ9897 as a DSA switch with a broadcom
> GENET network device as the DSA master device. At the time the system hangs
> the message "unregister_netdevice: waiting for eth0 to become free. Usage
> count = 2." is dumped periodically to the console.
> 
> After some investigation I found the reason to be unreleased references to
> the master device which are still held by the slave devices at the time the
> system is shut down (I have two slave devices in use).
> 
> While these references are supposed to be released in ksz_switch_remove()
> this function never gets the chance to be called due to the system hang at
> the master device deregistration which happens before ksz_switch_remove()
> is called.
> 
> The fix is to make sure that the master device references are already
> released when the device is unregistered. For this reason PATCH1 provides
> a new function dsa_tree_shutdown() that can be called by DSA drivers to
> untear the DSA switch at shutdown. PATCH2 uses this function in a new
> helper function for KSZ switches to properly shutdown the KSZ switch.
> PATCH 3 uses the new helper function in the KSZ9477 shutdown handler.
> 
> Theses patches have been tested on a Raspberry PI 5.10 kernel with a
> KSZ9897. The patches have been adjusted to apply against net-next and are
> compile tested with next-next.

Can you try this patch

commit 07b90056cb15ff9877dca0d8f1b6583d1051f724
Author: Vladimir Oltean <vladimir.oltean@nxp.com>
Date:   Tue Jan 12 01:09:43 2021 +0200

    net: dsa: unbind all switches from tree when DSA master unbinds

    Currently the following happens when a DSA master driver unbinds while
    there are DSA switches attached to it:

  parent reply	other threads:[~2021-09-09 10:15 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-09  9:53 [PATCH 0/3] Fix for KSZ DSA switch shutdown Lino Sanfilippo
2021-09-09  9:53 ` [PATCH 1/3] net: dsa: introduce function dsa_tree_shutdown() Lino Sanfilippo
2021-09-09  9:53 ` [PATCH 2/3] net: dsa: microchip: provide the function ksz_switch_shutdown() Lino Sanfilippo
2021-09-09  9:53 ` [PATCH 3/3] net: dsa: microchip: tear down DSA tree at system shutdown Lino Sanfilippo
2021-09-09 10:14 ` Vladimir Oltean [this message]
2021-09-09 11:08   ` [PATCH 0/3] Fix for KSZ DSA switch shutdown Lino Sanfilippo
2021-09-09 11:42     ` Vladimir Oltean
2021-09-09 12:56       ` Vladimir Oltean
2021-09-09 13:19         ` Aw: " Lino Sanfilippo
2021-09-09 14:29           ` Lino Sanfilippo
2021-09-09 15:17             ` Andrew Lunn
2021-09-09 16:41               ` Lino Sanfilippo
2021-09-09 15:11           ` Andrew Lunn
2021-09-09 16:46             ` Lino Sanfilippo
2021-09-09 17:55               ` Andrew Lunn
2021-09-09 15:47           ` Vladimir Oltean
2021-09-09 16:00             ` Florian Fainelli
2021-09-10  1:32               ` Saravana Kannan
2021-09-09 16:37             ` Lino Sanfilippo
2021-09-09 16:44               ` Florian Fainelli
2021-09-09 17:07                 ` Lino Sanfilippo
2021-09-09 22:54                   ` Vladimir Oltean
2021-09-09 23:23                     ` Vladimir Oltean
2021-09-10  1:08                       ` Vladimir Oltean
2021-09-10  2:15                     ` Florian Fainelli
2021-09-10 11:51                       ` Andrew Lunn
2021-09-10 14:58                         ` Vladimir Oltean
2021-09-11 11:44                           ` Vladimir Oltean
2021-09-12 20:19                           ` Lino Sanfilippo
2021-09-12 20:29                             ` Vladimir Oltean
2021-09-13 10:32                               ` Aw: " Lino Sanfilippo
2021-09-13 10:44                                 ` Vladimir Oltean
2021-09-13 11:01                                   ` Aw: " Lino Sanfilippo
2021-09-14 18:48                                     ` Vladimir Oltean
2021-09-15  5:42                                       ` Lino Sanfilippo
2021-09-18 19:37                                         ` Lino Sanfilippo
2021-09-18 22:04                                           ` Vladimir Oltean
2021-09-19  0:29                                             ` Vladimir Oltean
2021-09-09 12:40 ` Andrew Lunn

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