From: Lukas Wunner <lukas@wunner•de>
To: Kurt Kanzenbach <kurt@linutronix•de>, Roman Lozko <lozko.roma@gmail•com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel•com>,
Tony Nguyen <anthony.l.nguyen@intel•com>,
"David S. Miller" <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
Jakub Kicinski <kuba@kernel•org>, Paolo Abeni <pabeni@redhat•com>,
Andrew Lunn <andrew@lunn•ch>,
Sasha Neftin <sasha.neftin@intel•com>,
intel-wired-lan@lists•osuosl.org, netdev@vger•kernel.org
Subject: Re: [PATCH iwl-net] igc: Fix deadlock on module removal
Date: Sun, 14 Apr 2024 11:02:06 +0200 [thread overview]
Message-ID: <Zhubjkscu9HPgUcA@wunner.de> (raw)
In-Reply-To: <20240411-igc_led_deadlock-v1-1-0da98a3c68c5@linutronix.de>
[cc += Roman Lozko who originally reported the issue]
On Sun, Apr 14, 2024 at 09:44:10AM +0200, Kurt Kanzenbach wrote:
> unregister_netdev() acquires the RNTL lock and releases the LEDs bound
> to that netdevice. However, netdev_trig_deactivate() and later
> unregister_netdevice_notifier() try to acquire the RTNL lock again.
>
> Avoid this situation by not using the device-managed LED class
> functions.
>
> Suggested-by: Lukas Wunner <lukas@wunner•de>
> Fixes: ea578703b03d ("igc: Add support for LEDs on i225/i226")
> Signed-off-by: Kurt Kanzenbach <kurt@linutronix•de>
This patch is almost a 1:1 copy of the patch I submitted on April 5:
https://lore.kernel.org/all/ZhBN9p1yOyciXkzw@wunner.de/
I think it is mandatory that you include a Signed-off-by with my name
in that case. Arguably the commit author ("From:") should also be me.
Moreover this is missing a Reported-by tag with Roman Lozko's name.
AFAICS the only changes that you made are:
- rename igc_led_teardown() to igc_led_free()
- rename ret to err
- replace devm_kcalloc() with kcalloc()
(and you introduced a memory leak while doing so, see below)
Honestly I don't see how those small changes justify omitting a
Signed-off-by or assuming authorship.
I would have been happy to submit a patch myself, I was waiting
for a Tested-by from Roman or you.
> --- a/drivers/net/ethernet/intel/igc/igc.h
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -164,6 +164,8 @@ struct igc_ring {
> struct xsk_buff_pool *xsk_pool;
> } ____cacheline_internodealigned_in_smp;
>
> +struct igc_led_classdev;
Unnecessary forward declaration, this compiled fine for me without it.
> int igc_led_setup(struct igc_adapter *adapter)
> {
> struct net_device *netdev = adapter->netdev;
> - struct device *dev = &netdev->dev;
> struct igc_led_classdev *leds;
> - int i;
> + int i, err;
>
> mutex_init(&adapter->led_mutex);
>
> - leds = devm_kcalloc(dev, IGC_NUM_LEDS, sizeof(*leds), GFP_KERNEL);
> + leds = kcalloc(IGC_NUM_LEDS, sizeof(*leds), GFP_KERNEL);
> if (!leds)
> return -ENOMEM;
>
> - for (i = 0; i < IGC_NUM_LEDS; i++)
> - igc_setup_ldev(leds + i, netdev, i);
> + for (i = 0; i < IGC_NUM_LEDS; i++) {
> + err = igc_setup_ldev(leds + i, netdev, i);
> + if (err)
> + goto err;
> + }
> +
> + adapter->leds = leds;
>
> return 0;
> +
> +err:
> + for (i--; i >= 0; i--)
> + led_classdev_unregister(&((leds + i)->led));
> +
> + return err;
> +}
"leds" allocation is leaked in the error path.
This memory leak was not present in my original patch. Not good!
Thanks,
Lukas
next prev parent reply other threads:[~2024-04-14 9:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-14 7:44 [PATCH iwl-net] igc: Fix deadlock on module removal Kurt Kanzenbach
2024-04-14 9:02 ` Lukas Wunner [this message]
2024-04-14 9:15 ` Kurt Kanzenbach
2024-04-15 11:02 ` Kurt Kanzenbach
2024-04-15 13:54 ` Lukas Wunner
2024-04-15 14:00 ` Kurt Kanzenbach
2024-04-15 13:51 ` Lukas Wunner
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