lkml.org 
[lkml]   [2020]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH v3] video: fbdev: vesafb: add missed release_region
From
Date

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 <hslester96@gmail.com>
> ---
> 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

\
 
 \ /
  Last update: 2020-03-20 13:01    [W:0.066 / U:16.544 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site