The ax25_dev is managed by reference counting, so it should not be
deallocated directly by kfree() in ax25_dev_free(), replace it with
ax25_dev_put() instead.

Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
 net/ax25/ax25_dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 282ec581c07..07723095c60 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -208,7 +208,7 @@ void __exit ax25_dev_free(void)
 		s        = ax25_dev;
 		netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
 		ax25_dev = ax25_dev->next;
-		kfree(s);
+		ax25_dev_put(s);
 	}
 	ax25_dev_list = NULL;
 	spin_unlock_bh(&ax25_dev_lock);
-- 
2.17.1

> The ax25_dev is managed by reference counting, so it should not be
> deallocated directly by kfree() in ax25_dev_free(), replace it with
> ax25_dev_put() instead.

You repeated a wording mistake in the summary phrase from a previous cover letter.
Please avoid confusion about desired code replacements.
How do you think about to append parentheses to involved function names?


Would you find the following change description a bit nicer?

   The object “ax25_dev” is managed by reference counting.
   Thus it should not be directly released by a kfree() call in ax25_dev_free().
   Replace it with a ax25_dev_put() call instead.


Would you like to extend patch version descriptions (or changelogs) accordingly?

Regards,
Markus

On Fri, May 03, 2024 at 07:36:54AM +0200, Markus Elfring wrote:
> > The ax25_dev is managed by reference counting, so it should not be
> > deallocated directly by kfree() in ax25_dev_free(), replace it with
> > ax25_dev_put() instead.
> 
> You repeated a wording mistake in the summary phrase from a previous cover letter.

Yeah.  That's true.  The subject should be changed to:

Subject: [PATCH] ax25: change kfree() in ax25_dev_free() to ax25_dev_put()

Another option would be:

Subject: [PATCH] ax25: use ax25_dev_put() in ax25_dev_free()

Otherwise the commit message is okay as-is.

regards,
dan carpenter