The driver forgets to free the I/O region in remove and probe
failure.
Add the missed calls to fix it.
Signed-off-by: Chuhong Yuan <[email protected]>
---
Changes in v3:
- Revise the commit message.
- Add an error handler to suit the "goto error" before request_region().
- Revise the order of operations in remove.
drivers/video/fbdev/vesafb.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
index a1fe24ea869b..c7bc9ace47d4 100644
--- a/drivers/video/fbdev/vesafb.c
+++ b/drivers/video/fbdev/vesafb.c
@@ -439,7 +439,7 @@ static int vesafb_probe(struct platform_device *dev)
"vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
vesafb_fix.smem_len, vesafb_fix.smem_start);
err = -EIO;
- goto err;
+ goto err_release_region;
}
printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
@@ -458,15 +458,17 @@ static int vesafb_probe(struct platform_device *dev)
if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
err = -ENOMEM;
- goto err;
+ goto err_release_region;
}
if (register_framebuffer(info)<0) {
err = -EINVAL;
fb_dealloc_cmap(&info->cmap);
- goto err;
+ goto err_release_region;
}
fb_info(info, "%s frame buffer device\n", info->fix.id);
return 0;
+err_release_region:
+ release_region(0x3c0, 32);
err:
arch_phys_wc_del(par->wc_cookie);
if (info->screen_base)
@@ -481,6 +483,7 @@ static int vesafb_remove(struct platform_device *pdev)
struct fb_info *info = platform_get_drvdata(pdev);
unregister_framebuffer(info);
+ release_region(0x3c0, 32);
framebuffer_release(info);
return 0;
--
2.25.1
On 3/10/20 3:35 AM, Chuhong Yuan wrote:
> The driver forgets to free the I/O region in remove and probe
> failure.
> Add the missed calls to fix it.
>
> Signed-off-by: Chuhong Yuan <[email protected]>
> ---
> Changes in v3:
> - Revise the commit message.
> - Add an error handler to suit the "goto error" before request_region().
> - Revise the order of operations in remove.
>
> drivers/video/fbdev/vesafb.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
> index a1fe24ea869b..c7bc9ace47d4 100644
> --- a/drivers/video/fbdev/vesafb.c
> +++ b/drivers/video/fbdev/vesafb.c
> @@ -439,7 +439,7 @@ static int vesafb_probe(struct platform_device *dev)
> "vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
> vesafb_fix.smem_len, vesafb_fix.smem_start);
> err = -EIO;
> - goto err;
> + goto err_release_region;
> }
>
> printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
> @@ -458,15 +458,17 @@ static int vesafb_probe(struct platform_device *dev)
>
> if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
> err = -ENOMEM;
> - goto err;
> + goto err_release_region;
> }
> if (register_framebuffer(info)<0) {
> err = -EINVAL;
> fb_dealloc_cmap(&info->cmap);
> - goto err;
> + goto err_release_region;
> }
> fb_info(info, "%s frame buffer device\n", info->fix.id);
> return 0;
> +err_release_region:
> + release_region(0x3c0, 32);
This is incorrect.
The cleanup order should be the reverse of the probing order.
Also request_region() return value is not checked by the driver
(there is a comment that it can fail and is optional):
/* request failure does not faze us, as vgacon probably has this
* region already (FIXME) */
request_region(0x3c0, 32, "vesafb");
so what would happen in such case? It seems that unconditionally
doing the release will result in freeing the I/O region owned by
the other driver (vgacon)..
> err:
> arch_phys_wc_del(par->wc_cookie);
> if (info->screen_base)
> @@ -481,6 +483,7 @@ static int vesafb_remove(struct platform_device *pdev)
> struct fb_info *info = platform_get_drvdata(pdev);
>
> unregister_framebuffer(info);
> + release_region(0x3c0, 32);
> framebuffer_release(info);
>
> return 0;
>
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
On Fri, Mar 20, 2020 at 8:01 PM Bartlomiej Zolnierkiewicz
<[email protected]> wrote:
>
>
> On 3/10/20 3:35 AM, Chuhong Yuan wrote:
> > The driver forgets to free the I/O region in remove and probe
> > failure.
> > Add the missed calls to fix it.
> >
> > Signed-off-by: Chuhong Yuan <[email protected]>
> > ---
> > Changes in v3:
> > - Revise the commit message.
> > - Add an error handler to suit the "goto error" before request_region().
> > - Revise the order of operations in remove.
> >
> > drivers/video/fbdev/vesafb.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
> > index a1fe24ea869b..c7bc9ace47d4 100644
> > --- a/drivers/video/fbdev/vesafb.c
> > +++ b/drivers/video/fbdev/vesafb.c
> > @@ -439,7 +439,7 @@ static int vesafb_probe(struct platform_device *dev)
> > "vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
> > vesafb_fix.smem_len, vesafb_fix.smem_start);
> > err = -EIO;
> > - goto err;
> > + goto err_release_region;
> > }
> >
> > printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
> > @@ -458,15 +458,17 @@ static int vesafb_probe(struct platform_device *dev)
> >
> > if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
> > err = -ENOMEM;
> > - goto err;
> > + goto err_release_region;
> > }
> > if (register_framebuffer(info)<0) {
> > err = -EINVAL;
> > fb_dealloc_cmap(&info->cmap);
> > - goto err;
> > + goto err_release_region;
> > }
> > fb_info(info, "%s frame buffer device\n", info->fix.id);
> > return 0;
> > +err_release_region:
> > + release_region(0x3c0, 32);
>
> This is incorrect.
>
> The cleanup order should be the reverse of the probing order.
>
> Also request_region() return value is not checked by the driver
> (there is a comment that it can fail and is optional):
>
> /* request failure does not faze us, as vgacon probably has this
> * region already (FIXME) */
> request_region(0x3c0, 32, "vesafb");
>
> so what would happen in such case? It seems that unconditionally
> doing the release will result in freeing the I/O region owned by
> the other driver (vgacon)..
>
Maybe we can add a field to represent whether the request succeeds?
request_region() returns source *, we can store it and check whether
it is null when
we are going to call release_region().
> > err:
> > arch_phys_wc_del(par->wc_cookie);
> > if (info->screen_base)
> > @@ -481,6 +483,7 @@ static int vesafb_remove(struct platform_device *pdev)
> > struct fb_info *info = platform_get_drvdata(pdev);
> >
> > unregister_framebuffer(info);
> > + release_region(0x3c0, 32);
> > framebuffer_release(info);
> >
> > return 0;
> >
>
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
On 3/24/20 2:35 PM, Chuhong Yuan wrote:
> On Fri, Mar 20, 2020 at 8:01 PM Bartlomiej Zolnierkiewicz
> <[email protected]> wrote:
>>
>>
>> On 3/10/20 3:35 AM, Chuhong Yuan wrote:
>>> The driver forgets to free the I/O region in remove and probe
>>> failure.
>>> Add the missed calls to fix it.
>>>
>>> Signed-off-by: Chuhong Yuan <[email protected]>
>>> ---
>>> Changes in v3:
>>> - Revise the commit message.
>>> - Add an error handler to suit the "goto error" before request_region().
>>> - Revise the order of operations in remove.
>>>
>>> drivers/video/fbdev/vesafb.c | 9 ++++++---
>>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
>>> index a1fe24ea869b..c7bc9ace47d4 100644
>>> --- a/drivers/video/fbdev/vesafb.c
>>> +++ b/drivers/video/fbdev/vesafb.c
>>> @@ -439,7 +439,7 @@ static int vesafb_probe(struct platform_device *dev)
>>> "vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
>>> vesafb_fix.smem_len, vesafb_fix.smem_start);
>>> err = -EIO;
>>> - goto err;
>>> + goto err_release_region;
>>> }
>>>
>>> printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
>>> @@ -458,15 +458,17 @@ static int vesafb_probe(struct platform_device *dev)
>>>
>>> if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
>>> err = -ENOMEM;
>>> - goto err;
>>> + goto err_release_region;
>>> }
>>> if (register_framebuffer(info)<0) {
>>> err = -EINVAL;
>>> fb_dealloc_cmap(&info->cmap);
>>> - goto err;
>>> + goto err_release_region;
>>> }
>>> fb_info(info, "%s frame buffer device\n", info->fix.id);
>>> return 0;
>>> +err_release_region:
>>> + release_region(0x3c0, 32);
>>
>> This is incorrect.
>>
>> The cleanup order should be the reverse of the probing order.
>>
>> Also request_region() return value is not checked by the driver
>> (there is a comment that it can fail and is optional):
>>
>> /* request failure does not faze us, as vgacon probably has this
>> * region already (FIXME) */
>> request_region(0x3c0, 32, "vesafb");
>>
>> so what would happen in such case? It seems that unconditionally
>> doing the release will result in freeing the I/O region owned by
>> the other driver (vgacon)..
>>
>
> Maybe we can add a field to represent whether the request succeeds?
> request_region() returns source *, we can store it and check whether
> it is null when
> we are going to call release_region().
Yes, this is a preferred approach.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
>>> err:
>>> arch_phys_wc_del(par->wc_cookie);
>>> if (info->screen_base)
>>> @@ -481,6 +483,7 @@ static int vesafb_remove(struct platform_device *pdev)
>>> struct fb_info *info = platform_get_drvdata(pdev);
>>>
>>> unregister_framebuffer(info);
>>> + release_region(0x3c0, 32);
>>> framebuffer_release(info);
>>>
>>> return 0;
>>>
>>
>> Best regards,
>> --
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics