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[82.64.73.52]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-439b031c5casm56553085e9.39.2025.02.22.12.45.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Feb 2025 12:45:19 -0800 (PST) From: Dave Penkler To: gregkh@linuxfoundation.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Dave Penkler Subject: [PATCH] staging: gpib: Fix Oops after disconnect in agilent usb Date: Sat, 22 Feb 2025 21:45:15 +0100 Message-ID: <20250222204515.5104-1-dpenkler@gmail.com> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If the agilent usb dongle is disconnected subsequent calls to the driver cause a NULL dereference Oops as the bus_interface is set to NULL on disconnect. This problem was introduced by setting usb_dev from the bus_interface for dev_xxx messages. Previously bus_interface was checked for NULL only in the functions directly calling usb_fill_bulk_urb or usb_control_msg. Check for valid bus_interface on all interface entry points and return -ENODEV if it is NULL. Fixes: fbae7090f30c ("staging: gpib: Update messaging and usb_device refs i= n agilent_usb") Signed-off-by: Dave Penkler --- .../gpib/agilent_82357a/agilent_82357a.c | 65 ++++++++++++++++--- 1 file changed, 55 insertions(+), 10 deletions(-) diff --git a/drivers/staging/gpib/agilent_82357a/agilent_82357a.c b/drivers= /staging/gpib/agilent_82357a/agilent_82357a.c index 7ebebe00dc48..e0d36f0dff25 100644 --- a/drivers/staging/gpib/agilent_82357a/agilent_82357a.c +++ b/drivers/staging/gpib/agilent_82357a/agilent_82357a.c @@ -427,7 +427,7 @@ static int agilent_82357a_read(gpib_board_t *board, uin= t8_t *buffer, size_t leng { int retval; struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; u8 *out_data, *in_data; int out_data_length, in_data_length; int bytes_written, bytes_read; @@ -438,6 +438,10 @@ static int agilent_82357a_read(gpib_board_t *board, ui= nt8_t *buffer, size_t leng =20 *nbytes =3D 0; *end =3D 0; + + if (!a_priv->bus_interface) + return -ENODEV; + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); out_data_length =3D 0x9; out_data =3D kmalloc(out_data_length, GFP_KERNEL); if (!out_data) @@ -534,7 +538,7 @@ static ssize_t agilent_82357a_generic_write(gpib_board_= t *board, uint8_t *buffer { int retval; struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; u8 *out_data =3D NULL; u8 *status_data =3D NULL; int out_data_length; @@ -545,6 +549,10 @@ static ssize_t agilent_82357a_generic_write(gpib_board= _t *board, uint8_t *buffer struct agilent_82357a_register_pairlet read_reg; =20 *bytes_written =3D 0; + if (!a_priv->bus_interface) + return -ENODEV; + + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); out_data_length =3D length + 0x8; out_data =3D kmalloc(out_data_length, GFP_KERNEL); if (!out_data) @@ -697,9 +705,13 @@ int agilent_82357a_take_control_internal(gpib_board_t = *board, int synchronous) =20 static int agilent_82357a_take_control(gpib_board_t *board, int synchronou= s) { + struct agilent_82357a_priv *a_priv =3D board->private_data; const int timeout =3D 10; int i; =20 + if (!a_priv->bus_interface) + return -ENODEV; + /* It looks like the 9914 does not handle tcs properly. * See comment above tms9914_take_control_workaround() in * drivers/gpib/tms9914/tms9914_aux.c @@ -723,10 +735,14 @@ static int agilent_82357a_take_control(gpib_board_t *= board, int synchronous) static int agilent_82357a_go_to_standby(gpib_board_t *board) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet write; int retval; =20 + if (!a_priv->bus_interface) + return -ENODEV; + + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); write.address =3D AUXCR; write.value =3D AUX_GTS; retval =3D agilent_82357a_write_registers(a_priv, &write, 1); @@ -739,11 +755,15 @@ static int agilent_82357a_go_to_standby(gpib_board_t = *board) static void agilent_82357a_request_system_control(gpib_board_t *board, int= request_control) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet writes[2]; int retval; int i =3D 0; =20 + if (!a_priv->bus_interface) + return; // -ENODEV; + + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); /* 82357B needs bit to be set in 9914 AUXCR register */ writes[i].address =3D AUXCR; if (request_control) { @@ -767,10 +787,14 @@ static void agilent_82357a_request_system_control(gpi= b_board_t *board, int reque static void agilent_82357a_interface_clear(gpib_board_t *board, int assert) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet write; int retval; =20 + if (!a_priv->bus_interface) + return; // -ENODEV; + + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); write.address =3D AUXCR; write.value =3D AUX_SIC; if (assert) { @@ -785,10 +809,14 @@ static void agilent_82357a_interface_clear(gpib_board= _t *board, int assert) static void agilent_82357a_remote_enable(gpib_board_t *board, int enable) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet write; int retval; =20 + if (!a_priv->bus_interface) + return; //-ENODEV; + + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); write.address =3D AUXCR; write.value =3D AUX_SRE; if (enable) @@ -804,6 +832,8 @@ static int agilent_82357a_enable_eos(gpib_board_t *boar= d, uint8_t eos_byte, int { struct agilent_82357a_priv *a_priv =3D board->private_data; =20 + if (!a_priv->bus_interface) + return -ENODEV; if (compare_8_bits =3D=3D 0) return -EOPNOTSUPP; =20 @@ -822,10 +852,13 @@ static void agilent_82357a_disable_eos(gpib_board_t *= board) static unsigned int agilent_82357a_update_status(gpib_board_t *board, unsi= gned int clear_mask) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet address_status, bus_status; int retval; =20 + if (!a_priv->bus_interface) + return -ENODEV; + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); board->status &=3D ~clear_mask; if (a_priv->is_cic) set_bit(CIC_NUM, &board->status); @@ -885,6 +918,9 @@ static int agilent_82357a_primary_address(gpib_board_t = *board, unsigned int addr struct agilent_82357a_register_pairlet write; int retval; =20 + if (!a_priv->bus_interface) + return -ENODEV; + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); // put primary address in address0 write.address =3D ADR; write.value =3D address & ADDRESS_MASK; @@ -906,11 +942,14 @@ static int agilent_82357a_secondary_address(gpib_boar= d_t *board, unsigned int ad static int agilent_82357a_parallel_poll(gpib_board_t *board, uint8_t *resu= lt) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet writes[2]; struct agilent_82357a_register_pairlet read; int retval; =20 + if (!a_priv->bus_interface) + return -ENODEV; + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); // execute parallel poll writes[0].address =3D AUXCR; writes[0].value =3D AUX_CS | AUX_RPP; @@ -975,11 +1014,14 @@ static void agilent_82357a_return_to_local(gpib_boar= d_t *board) static int agilent_82357a_line_status(const gpib_board_t *board) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet bus_status; int retval; int status =3D ValidALL; =20 + if (!a_priv->bus_interface) + return -ENODEV; + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); bus_status.address =3D BSR; retval =3D agilent_82357a_read_registers(a_priv, &bus_status, 1, 0); if (retval) { @@ -1025,10 +1067,13 @@ static unsigned short nanosec_to_fast_talker_bits(u= nsigned int *nanosec) static unsigned int agilent_82357a_t1_delay(gpib_board_t *board, unsigned = int nanosec) { struct agilent_82357a_priv *a_priv =3D board->private_data; - struct usb_device *usb_dev =3D interface_to_usbdev(a_priv->bus_interface); + struct usb_device *usb_dev; struct agilent_82357a_register_pairlet write; int retval; =20 + if (!a_priv->bus_interface) + return -ENODEV; + usb_dev =3D interface_to_usbdev(a_priv->bus_interface); write.address =3D FAST_TALKER_T1; write.value =3D nanosec_to_fast_talker_bits(&nanosec); retval =3D agilent_82357a_write_registers(a_priv, &write, 1); --=20 2.48.1