linux-kernel - Re: [PATCH v2] vboxguest: Do not use devm for irq

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Date:   Sun, 12 Jun 2022 16:13:24 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Pascal Terjan <pterjan@...gle.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] vboxguest: Do not use devm for irq

Hi,

On 6/12/22 15:37, Pascal Terjan wrote:
> When relying on devm it doesn't get freed early enough which causes the
> following warning when unloading the module:
> 
> [249348.837181] remove_proc_entry: removing non-empty directory 'irq/20', leaking at least 'vboxguest'
> [249348.837219] WARNING: CPU: 0 PID: 6708 at fs/proc/generic.c:715 remove_proc_entry+0x119/0x140
> 
> [249348.837379] Call Trace:
> [249348.837385]  unregister_irq_proc+0xbd/0xe0
> [249348.837392]  free_desc+0x23/0x60
> [249348.837396]  irq_free_descs+0x4a/0x70
> [249348.837401]  irq_domain_free_irqs+0x160/0x1a0
> [249348.837452]  mp_unmap_irq+0x5c/0x60
> [249348.837458]  acpi_unregister_gsi_ioapic+0x29/0x40
> [249348.837463]  acpi_unregister_gsi+0x17/0x30
> [249348.837467]  acpi_pci_irq_disable+0xbf/0xe0
> [249348.837473]  pcibios_disable_device+0x20/0x30
> [249348.837478]  pci_disable_device+0xef/0x120
> [249348.837482]  vbg_pci_remove+0x6c/0x70 [vboxguest]
> 
> Signed-off-by: Pascal Terjan <pterjan@...gle.com>
> ---
> v2: stop using devm rather than adding a manual devm_free_irq

Thanks, v2 looks good to me:

Reviewed-by: Hans de Goede <hdegoede@...hat.com>

Regards,

Hans



> 
>  drivers/virt/vboxguest/vboxguest_linux.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/virt/vboxguest/vboxguest_linux.c b/drivers/virt/vboxguest/vboxguest_linux.c
> index 6e8c0f1c1056..dec36934d679 100644
> --- a/drivers/virt/vboxguest/vboxguest_linux.c
> +++ b/drivers/virt/vboxguest/vboxguest_linux.c
> @@ -360,8 +360,8 @@ static int vbg_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
>  		goto err_vbg_core_exit;
>  	}
>  
> -	ret = devm_request_irq(dev, pci->irq, vbg_core_isr, IRQF_SHARED,
> -			       DEVICE_NAME, gdev);
> +	ret = request_irq(pci->irq, vbg_core_isr, IRQF_SHARED, DEVICE_NAME,
> +			  gdev);
>  	if (ret) {
>  		vbg_err("vboxguest: Error requesting irq: %d\n", ret);
>  		goto err_vbg_core_exit;
> @@ -371,7 +371,7 @@ static int vbg_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
>  	if (ret) {
>  		vbg_err("vboxguest: Error misc_register %s failed: %d\n",
>  			DEVICE_NAME, ret);
> -		goto err_vbg_core_exit;
> +		goto err_free_irq;
>  	}
>  
>  	ret = misc_register(&gdev->misc_device_user);
> @@ -407,6 +407,8 @@ static int vbg_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
>  	misc_deregister(&gdev->misc_device_user);
>  err_unregister_misc_device:
>  	misc_deregister(&gdev->misc_device);
> +err_free_irq:
> +	free_irq(pci->irq, gdev);
>  err_vbg_core_exit:
>  	vbg_core_exit(gdev);
>  err_disable_pcidev:
> @@ -423,6 +425,7 @@ static void vbg_pci_remove(struct pci_dev *pci)
>  	vbg_gdev = NULL;
>  	mutex_unlock(&vbg_gdev_mutex);
>  
> +	free_irq(pci->irq, gdev);
>  	device_remove_file(gdev->dev, &dev_attr_host_features);
>  	device_remove_file(gdev->dev, &dev_attr_host_version);
>  	misc_deregister(&gdev->misc_device_user);