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[82.64.73.52]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38bf3221b7fsm5631637f8f.27.2025.01.18.09.30.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Jan 2025 09:30:04 -0800 (PST) Date: Sat, 18 Jan 2025 18:30:03 +0100 From: Dave Penkler To: Greg KH Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] staging: gpib: Fix NULL pointer dereference in detach Message-ID: References: <20250118145046.12181-1-dpenkler@gmail.com> <20250118145046.12181-2-dpenkler@gmail.com> <2025011830-whoopee-dormitory-82da@gregkh> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2025011830-whoopee-dormitory-82da@gregkh> On Sat, Jan 18, 2025 at 04:36:15PM +0100, Greg KH wrote: > On Sat, Jan 18, 2025 at 03:50:45PM +0100, Dave Penkler wrote: > > When the detach function is called after a failed attach > > the usb_dev initialization can cause a NULL pointer > > dereference. This happens when the usb device is not found > > in the attach procedure. > > > > Remove the usb_dev variable and initialization and change the dev > > in the dev_info message from the usb_dev to the gpib_dev. > > > > Fixes: fbae7090f30c ("staging: gpib: Update messaging and usb_device refs in agilent_usb") > > Signed-off-by: Dave Penkler > > --- > > drivers/staging/gpib/agilent_82357a/agilent_82357a.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/staging/gpib/agilent_82357a/agilent_82357a.c b/drivers/staging/gpib/agilent_82357a/agilent_82357a.c > > index 34d85a1bdb37..2aaccebc3c7b 100644 > > --- a/drivers/staging/gpib/agilent_82357a/agilent_82357a.c > > +++ b/drivers/staging/gpib/agilent_82357a/agilent_82357a.c > > @@ -1442,12 +1442,10 @@ static int agilent_82357a_go_idle(gpib_board_t *board) > > static void agilent_82357a_detach(gpib_board_t *board) > > { > > struct agilent_82357a_priv *a_priv; > > - struct usb_device *usb_dev; > > > > mutex_lock(&agilent_82357a_hotplug_lock); > > > > a_priv = board->private_data; > > - usb_dev = interface_to_usbdev(a_priv->bus_interface); > > if (a_priv) { > > if (a_priv->bus_interface) { > > agilent_82357a_go_idle(board); > > @@ -1459,7 +1457,7 @@ static void agilent_82357a_detach(gpib_board_t *board) > > agilent_82357a_cleanup_urbs(a_priv); > > agilent_82357a_free_private(a_priv); > > } > > - dev_info(&usb_dev->dev, "%s: detached\n", __func__); > > + dev_info(board->gpib_dev, "%s: detached\n", __func__); > > In the future, these dev_info() lines all need to go away as when > drivers work properly, they should be quiet. I'll take this fix for now > as it's needed, just something to plan on for the future cleanups here. > > thanks, > > greg k-h OK thanks, -dave