Re: [PATCH] net: wireless: convert WARN_ON() to pr_warn() in cfg80211_sme_connect

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Apr 07, 2021 at 10:19:03AM +0800, Du Cheng wrote:
> A WARN_ON(wdev->conn) would trigger in cfg80211_sme_connect(), if
> multiple send_msg() system calls are made from the userland, which
> should be anticipated and handled by the wireless driver. Convert this
> WARN() to pr_warn to prevent a kernel panic if kernel is configured to
> "panic on warn".
> 
> Bug reported by syzbot.
> 
> Reported-by: syzbot+5f9392825de654244975@syzkaller.appspotmail.com
> Signed-off-by: Du Cheng <ducheng2@gmail.com>
> ---
> link to syzkaller:
> https://syzkaller.appspot.com/bug?extid=5f9392825de654244975
> this patch has passed syzbot test.
>  net/wireless/sme.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/wireless/sme.c b/net/wireless/sme.c
> index 07756ca5e3b5..87a65a4c40ae 100644
> --- a/net/wireless/sme.c
> +++ b/net/wireless/sme.c
> @@ -529,8 +529,10 @@ static int cfg80211_sme_connect(struct wireless_dev *wdev,
>  		cfg80211_sme_free(wdev);
>  	}
>  
> -	if (WARN_ON(wdev->conn))
> +	if (wdev->conn) {
> +		pr_warn("%s: wdev->conn != NULL, sme connect in progress", __func__);

You have a real device, please always use 'dev_warn() for stuff like
this, or the netdev equivalent.  Also no need for __func__ for stuff
like this, that's just clutter.

Also, what can a user do if they get this information?  What does it
mean to them?  Try making the text more informative.

thanks,

greg k-h