Re: [PATCH net] s390/qeth: fix use-after-free in hsci

[Leon Romanovsky <leon@kernel.org>]

On Tue, Dec 06, 2022 at 03:56:14PM +0100, Alexandra Winter wrote:
> KASAN found that addr was dereferenced after br2dev_event_work was freed.

Please add KASAN report to be part of commit message.

Thanks

> 
> Fixes: f7936b7b2663 ("s390/qeth: Update MACs of LEARNING_SYNC device")
> Reported-by: Thorsten Winkler <twinkler@linux.ibm.com>
> Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
> Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
> Reviewed-by: Thorsten Winkler <twinkler@linux.ibm.com>
> ---
>  drivers/s390/net/qeth_l2_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
> index 9dc935886e9f..c6ded3fdd715 100644
> --- a/drivers/s390/net/qeth_l2_main.c
> +++ b/drivers/s390/net/qeth_l2_main.c
> @@ -758,7 +758,6 @@ static void qeth_l2_br2dev_worker(struct work_struct *work)
>  	struct list_head *iter;
>  	int err = 0;
>  
> -	kfree(br2dev_event_work);
>  	QETH_CARD_TEXT_(card, 4, "b2dw%04lx", event);
>  	QETH_CARD_TEXT_(card, 4, "ma%012llx", ether_addr_to_u64(addr));
>  
> @@ -815,6 +814,7 @@ static void qeth_l2_br2dev_worker(struct work_struct *work)
>  	dev_put(brdev);
>  	dev_put(lsyncdev);
>  	dev_put(dstdev);
> +	kfree(br2dev_event_work);
>  }
>  
>  static int qeth_l2_br2dev_queue_work(struct net_device *brdev,
> -- 
> 2.34.1
>