Re: [PATCH] drm/bochs: Drop manual put on probe error path

Re: [PATCH] drm/bochs: Drop manual put on probe error path

[Thomas Zimmermann]

Am 24.04.26 um 14:34 schrieb Myeonghun Pak:
> bochs_pci_probe() allocates the DRM device with devm_drm_dev_alloc(),
> which registers a devres action to drop the initial DRM device reference
> on driver detach or probe failure.
>
> The error path currently calls drm_dev_put() manually. If probe then
> returns an error, devres will run the registered release action and put
> the same device again, after the first put may already have released it.
>
> Return the probe error directly and let devres own the final put.
>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>

Fixes: 04826f588682 ("drm/bochs: Allocate DRM device in struct 
bochs_device")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: virtualization@lists.linux.dev
Cc: <stable@vger.kernel.org> # v6.13+


> ---
>   drivers/gpu/drm/tiny/bochs.c | 10 +++-------
>   1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
> index 222e4ae1ab..5d8dc5efec 100644
> --- a/drivers/gpu/drm/tiny/bochs.c
> +++ b/drivers/gpu/drm/tiny/bochs.c
> @@ -761,25 +761,21 @@ static int bochs_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent
>   
>   	ret = pcim_enable_device(pdev);
>   	if (ret)
> -		goto err_free_dev;
> +		return ret;
>   
>   	pci_set_drvdata(pdev, dev);
>   
>   	ret = bochs_load(bochs);
>   	if (ret)
> -		goto err_free_dev;
> +		return ret;
>   
>   	ret = drm_dev_register(dev, 0);
>   	if (ret)
> -		goto err_free_dev;
> +		return ret;
>   
>   	drm_client_setup(dev, NULL);
>   
>   	return ret;
> -
> -err_free_dev:
> -	drm_dev_put(dev);
> -	return ret;
>   }
>   
>   static void bochs_pci_remove(struct pci_dev *pdev)

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)

Re: drm/bochs: Drop manual put on probe error path

[Markus Elfring]

…
> > Return the probe error directly and let devres own the final put.
…
> Fixes: 04826f588682 ("drm/bochs: Allocate DRM device in struct 
> bochs_device")
…

See also once more:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v7.1-rc2#n145

Regards,
Markus