lkml.org 
[lkml]   [2021]   [Dec]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] fsi: Aspeed: Fix a potential double free
On Sun, Dec 26, 2021 at 05:56:02PM +0100, Christophe JAILLET wrote:
> 'aspeed' is a devm_alloc'ed, so there is no need to free it explicitly or
> there will be a double free().

A struct device can never be devm_alloced for obvious reasons. Perhaps
that is the real problem here?

> Remove the 'release' function that is wrong and unneeded.
>
> Fixes: 606397d67f41 ("fsi: Add ast2600 master driver")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> This patch is completely theoretical. It looks good to me, but there is a
> little too much indirections for me. I'm also not that familiar with
> fixing issue related to 'release' function...
>
> ... So review with care :)
> ---
> drivers/fsi/fsi-master-aspeed.c | 9 ---------
> 1 file changed, 9 deletions(-)
>
> diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
> index 8606e55c1721..4a745ccb60cf 100644
> --- a/drivers/fsi/fsi-master-aspeed.c
> +++ b/drivers/fsi/fsi-master-aspeed.c
> @@ -373,14 +373,6 @@ static int aspeed_master_break(struct fsi_master *master, int link)
> return aspeed_master_write(master, link, 0, addr, &cmd, 4);
> }
>
> -static void aspeed_master_release(struct device *dev)
> -{
> - struct fsi_master_aspeed *aspeed =
> - to_fsi_master_aspeed(dev_to_fsi_master(dev));
> -
> - kfree(aspeed);
> -}
> -
> /* mmode encoders */
> static inline u32 fsi_mmode_crs0(u32 x)
> {
> @@ -603,7 +595,6 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev)
> dev_info(&pdev->dev, "hub version %08x (%d links)\n", reg, links);
>
> aspeed->master.dev.parent = &pdev->dev;
> - aspeed->master.dev.release = aspeed_master_release;

Odd, then what deletes this device structure when the release function
wants to be called? You should have gotten a big warning from the
kernel when removing the device from the system at runtime, did you test
this somehow?

This does not look correct at all.

greg k-h

\
 
 \ /
  Last update: 2021-12-27 07:30    [W:0.061 / U:1.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site