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Date:   Mon, 7 Jun 2021 11:35:42 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Wenli Looi <wlooi@ucalgary.ca>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
        "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Subject: Re: [PATCH v2] staging: rtl8723bs: Fix uninitialized variable
Message-ID: <20210607083542.GP1955@kadam>
References: <7256195.zb9d8qvCYo@linux.local>
 <20210606184638.13650-1-wlooi@ucalgary.ca>
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On Sun, Jun 06, 2021 at 11:46:38AM -0700, Wenli Looi wrote:
> Uninitialized struct with invalid pointer causes BUG and prevents access
> point from working. Access point works once I apply this patch.
> 
> This problem seems to have been present from the time the driver was
> added to staging. Most users probably do not use access point so they
> will not encounter this bug.
> 
> https://forum.armbian.com/topic/14727-wifi-ap-kernel-bug-in-kernel-5444/
> has more details.
> 
> kzalloc() seems to be what other drivers are doing in the same situation
> of creating struct station_info and calling cfg80211_new_sta.  In
> particular, other drivers like ath6kl and mwifiex will silently return
> when kzalloc fails, so this seems like the right behavior. (mwifiex
> returns -ENOMEM from the place kzalloc is called, but if you follow the
> chain of calls, the return value is ultimately ignored)
> 
> Links to same situation in other drivers:
> https://github.com/torvalds/linux/blob/f5b6eb1e018203913dfefcf6fa988649ad11ad6e/drivers/net/wireless/ath/ath6kl/main.c#L488
> https://github.com/torvalds/linux/blob/f5b6eb1e018203913dfefcf6fa988649ad11ad6e/drivers/net/wireless/marvell/mwifiex/uap_event.c#L120
> 
> Signed-off-by: Wenli Looi <wlooi@ucalgary.ca>
> ---
> 
> v1 -> v2: Switched from large stack variable to kzalloc


Nah, v1 was better, it just needs an updated commit message.  See my
other email for more details.

regards,
dan carpenter