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Date: Tue, 10 Oct 2023 08:00:14 +0200
From: Greg KH <gregkh@linuxfoundation.org>
To: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: Peter Korsgaard <peter@korsgaard.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	syzbot+1f53a30781af65d2c955@syzkaller.appspotmail.com,
	netdev@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] net: usb: dm9601: fix uninitialized variable use in
 dm9601_mdio_read
Message-ID: <2023101036-fleshy-dude-aec0@gregkh>
References: <20231009-topic-dm9601_uninit_mdio_read-v2-1-f2fe39739b6c@gmail.com>
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In-Reply-To: <20231009-topic-dm9601_uninit_mdio_read-v2-1-f2fe39739b6c@gmail.com>

On Tue, Oct 10, 2023 at 12:26:14AM +0200, Javier Carrasco wrote:
> syzbot has found an uninit-value bug triggered by the dm9601 driver [1].
> 
> This error happens because the variable res is not updated if the call
> to dm_read_shared_word returns an error. In this particular case -EPROTO
> was returned and res stayed uninitialized.
> 
> This can be avoided by checking the return value of dm_read_shared_word
> and propagating the error if the read operation failed.
> 
> [1] https://syzkaller.appspot.com/bug?extid=1f53a30781af65d2c955
> 
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
> Reported-and-tested-by: syzbot+1f53a30781af65d2c955@syzkaller.appspotmail.com
> ---
> Changes in v2:
> - Remove unnecessary 'err == 0' case
> - Link to v1: https://lore.kernel.org/r/20231009-topic-dm9601_uninit_mdio_read-v1-1-d4d775e24e3b@gmail.com
> ---
>  drivers/net/usb/dm9601.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

What commit id does this fix?

thanks,

greg k-h