<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/net/can, branch v5.17.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>can: mcp251xfd: mcp251xfd_register_get_dev_id(): fix return of error value</title>
<updated>2022-04-08T11:58:54+00:00</updated>
<author>
<name>Tom Rix</name>
<email>trix@redhat.com</email>
</author>
<published>2022-03-19T15:31:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bcb0ab16bf84d99b7aee3c072f47e0f9c9fcdbbb'/>
<id>bcb0ab16bf84d99b7aee3c072f47e0f9c9fcdbbb</id>
<content type='text'>
commit fa7b514d2b2894e052b8e94c7a29feb98e90093f upstream.

Clang static analysis reports this issue:

| mcp251xfd-core.c:1813:7: warning: The left operand
|   of '&amp;' is a garbage value
|   FIELD_GET(MCP251XFD_REG_DEVID_ID_MASK, dev_id),
|   ^                                      ~~~~~~

dev_id is set in a successful call to mcp251xfd_register_get_dev_id().
Though the status of calls made by mcp251xfd_register_get_dev_id() are
checked and handled, their status' are not returned. So return err.

Fixes: 55e5b97f003e ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN")
Link: https://lore.kernel.org/all/20220319153128.2164120-1-trix@redhat.com
Signed-off-by: Tom Rix &lt;trix@redhat.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fa7b514d2b2894e052b8e94c7a29feb98e90093f upstream.

Clang static analysis reports this issue:

| mcp251xfd-core.c:1813:7: warning: The left operand
|   of '&amp;' is a garbage value
|   FIELD_GET(MCP251XFD_REG_DEVID_ID_MASK, dev_id),
|   ^                                      ~~~~~~

dev_id is set in a successful call to mcp251xfd_register_get_dev_id().
Though the status of calls made by mcp251xfd_register_get_dev_id() are
checked and handled, their status' are not returned. So return err.

Fixes: 55e5b97f003e ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN")
Link: https://lore.kernel.org/all/20220319153128.2164120-1-trix@redhat.com
Signed-off-by: Tom Rix &lt;trix@redhat.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: mcba_usb: properly check endpoint type</title>
<updated>2022-04-08T11:58:54+00:00</updated>
<author>
<name>Pavel Skripkin</name>
<email>paskripkin@gmail.com</email>
</author>
<published>2022-03-13T10:09:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f2ec3cd0f34f8c3f94bc21fbba14868301c9c49d'/>
<id>f2ec3cd0f34f8c3f94bc21fbba14868301c9c49d</id>
<content type='text'>
commit 136bed0bfd3bc9c95c88aafff2d22ecb3a919f23 upstream.

Syzbot reported warning in usb_submit_urb() which is caused by wrong
endpoint type. We should check that in endpoint is actually present to
prevent this warning.

Found pipes are now saved to struct mcba_priv and code uses them
directly instead of making pipes in place.

Fail log:

| usb 5-1: BOGUS urb xfer, pipe 3 != type 1
| WARNING: CPU: 1 PID: 49 at drivers/usb/core/urb.c:502 usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
| Modules linked in:
| CPU: 1 PID: 49 Comm: kworker/1:2 Not tainted 5.17.0-rc6-syzkaller-00184-g38f80f42147f #0
| Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
| Workqueue: usb_hub_wq hub_event
| RIP: 0010:usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
| ...
| Call Trace:
|  &lt;TASK&gt;
|  mcba_usb_start drivers/net/can/usb/mcba_usb.c:662 [inline]
|  mcba_usb_probe+0x8a3/0xc50 drivers/net/can/usb/mcba_usb.c:858
|  usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396
|  call_driver_probe drivers/base/dd.c:517 [inline]

Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Link: https://lore.kernel.org/all/20220313100903.10868-1-paskripkin@gmail.com
Reported-and-tested-by: syzbot+3bc1dce0cc0052d60fde@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin &lt;paskripkin@gmail.com&gt;
Reviewed-by: Vincent Mailhol &lt;mailhol.vincent@wanadoo.fr&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 136bed0bfd3bc9c95c88aafff2d22ecb3a919f23 upstream.

Syzbot reported warning in usb_submit_urb() which is caused by wrong
endpoint type. We should check that in endpoint is actually present to
prevent this warning.

Found pipes are now saved to struct mcba_priv and code uses them
directly instead of making pipes in place.

Fail log:

| usb 5-1: BOGUS urb xfer, pipe 3 != type 1
| WARNING: CPU: 1 PID: 49 at drivers/usb/core/urb.c:502 usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
| Modules linked in:
| CPU: 1 PID: 49 Comm: kworker/1:2 Not tainted 5.17.0-rc6-syzkaller-00184-g38f80f42147f #0
| Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
| Workqueue: usb_hub_wq hub_event
| RIP: 0010:usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
| ...
| Call Trace:
|  &lt;TASK&gt;
|  mcba_usb_start drivers/net/can/usb/mcba_usb.c:662 [inline]
|  mcba_usb_probe+0x8a3/0xc50 drivers/net/can/usb/mcba_usb.c:858
|  usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396
|  call_driver_probe drivers/base/dd.c:517 [inline]

Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Link: https://lore.kernel.org/all/20220313100903.10868-1-paskripkin@gmail.com
Reported-and-tested-by: syzbot+3bc1dce0cc0052d60fde@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin &lt;paskripkin@gmail.com&gt;
Reviewed-by: Vincent Mailhol &lt;mailhol.vincent@wanadoo.fr&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: mcba_usb: mcba_usb_start_xmit(): fix double dev_kfree_skb in error path</title>
<updated>2022-04-08T11:58:54+00:00</updated>
<author>
<name>Hangyu Hua</name>
<email>hbh25y@gmail.com</email>
</author>
<published>2022-03-11T08:02:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=42a4b0dfd365c4f77f96fd1f73a64b47ae443a38'/>
<id>42a4b0dfd365c4f77f96fd1f73a64b47ae443a38</id>
<content type='text'>
commit 04c9b00ba83594a29813d6b1fb8fdc93a3915174 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
because can_put_echo_skb() deletes original skb and
can_free_echo_skb() deletes the cloned skb.

Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Link: https://lore.kernel.org/all/20220311080208.45047-1-hbh25y@gmail.com
Signed-off-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 04c9b00ba83594a29813d6b1fb8fdc93a3915174 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
because can_put_echo_skb() deletes original skb and
can_free_echo_skb() deletes the cloned skb.

Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Link: https://lore.kernel.org/all/20220311080208.45047-1-hbh25y@gmail.com
Signed-off-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vxcan: enable local echo for sent CAN frames</title>
<updated>2022-04-08T11:58:17+00:00</updated>
<author>
<name>Oliver Hartkopp</name>
<email>socketcan@hartkopp.net</email>
</author>
<published>2022-03-09T12:04:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b1b4345ce83e6e04c3cc055f22eaaa20bdbb60c1'/>
<id>b1b4345ce83e6e04c3cc055f22eaaa20bdbb60c1</id>
<content type='text'>
[ Upstream commit 259bdba27e32368b4404f69d613b1c1014c07cbf ]

The vxcan driver provides a pair of virtual CAN interfaces to exchange
CAN traffic between different namespaces - analogue to veth.

In opposite to the vcan driver the local sent CAN traffic on this interface
is not echo'ed back but only sent to the remote peer. This is unusual and
can be easily fixed by removing IFF_ECHO from the netdevice flags that
are set for vxcan interfaces by default at startup.

Without IFF_ECHO set on driver level, the local sent CAN frames are echo'ed
in af_can.c in can_send(). This patch makes vxcan interfaces adopt the
same local echo behavior and procedures as known from the vcan interfaces.

Fixes: a8f820a380a2 ("can: add Virtual CAN Tunnel driver (vxcan)")
Link: https://lore.kernel.org/all/20220309120416.83514-5-socketcan@hartkopp.net
Signed-off-by: Oliver Hartkopp &lt;socketcan@hartkopp.net&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 259bdba27e32368b4404f69d613b1c1014c07cbf ]

The vxcan driver provides a pair of virtual CAN interfaces to exchange
CAN traffic between different namespaces - analogue to veth.

In opposite to the vcan driver the local sent CAN traffic on this interface
is not echo'ed back but only sent to the remote peer. This is unusual and
can be easily fixed by removing IFF_ECHO from the netdevice flags that
are set for vxcan interfaces by default at startup.

Without IFF_ECHO set on driver level, the local sent CAN frames are echo'ed
in af_can.c in can_send(). This patch makes vxcan interfaces adopt the
same local echo behavior and procedures as known from the vcan interfaces.

Fixes: a8f820a380a2 ("can: add Virtual CAN Tunnel driver (vxcan)")
Link: https://lore.kernel.org/all/20220309120416.83514-5-socketcan@hartkopp.net
Signed-off-by: Oliver Hartkopp &lt;socketcan@hartkopp.net&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: usb_8dev: usb_8dev_start_xmit(): fix double dev_kfree_skb() in error path</title>
<updated>2022-04-08T11:57:19+00:00</updated>
<author>
<name>Hangyu Hua</name>
<email>hbh25y@gmail.com</email>
</author>
<published>2022-03-11T08:06:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=29d6c06168faa23ce23db3321981c8fde576c95c'/>
<id>29d6c06168faa23ce23db3321981c8fde576c95c</id>
<content type='text'>
commit 3d3925ff6433f98992685a9679613a2cc97f3ce2 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
because can_put_echo_skb() deletes original skb and
can_free_echo_skb() deletes the cloned skb.

Fixes: 0024d8ad1639 ("can: usb_8dev: Add support for USB2CAN interface from 8 devices")
Link: https://lore.kernel.org/all/20220311080614.45229-1-hbh25y@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3d3925ff6433f98992685a9679613a2cc97f3ce2 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
because can_put_echo_skb() deletes original skb and
can_free_echo_skb() deletes the cloned skb.

Fixes: 0024d8ad1639 ("can: usb_8dev: Add support for USB2CAN interface from 8 devices")
Link: https://lore.kernel.org/all/20220311080614.45229-1-hbh25y@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: m_can: m_can_tx_handler(): fix use after free of skb</title>
<updated>2022-04-08T11:57:19+00:00</updated>
<author>
<name>Marc Kleine-Budde</name>
<email>mkl@pengutronix.de</email>
</author>
<published>2022-03-17T07:57:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=31417073493f302d26ab66b3abc098d43227b835'/>
<id>31417073493f302d26ab66b3abc098d43227b835</id>
<content type='text'>
commit 2e8e79c416aae1de224c0f1860f2e3350fa171f8 upstream.

can_put_echo_skb() will clone skb then free the skb. Move the
can_put_echo_skb() for the m_can version 3.0.x directly before the
start of the xmit in hardware, similar to the 3.1.x branch.

Fixes: 80646733f11c ("can: m_can: update to support CAN FD features")
Link: https://lore.kernel.org/all/20220317081305.739554-1-mkl@pengutronix.de
Cc: stable@vger.kernel.org
Reported-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2e8e79c416aae1de224c0f1860f2e3350fa171f8 upstream.

can_put_echo_skb() will clone skb then free the skb. Move the
can_put_echo_skb() for the m_can version 3.0.x directly before the
start of the xmit in hardware, similar to the 3.1.x branch.

Fixes: 80646733f11c ("can: m_can: update to support CAN FD features")
Link: https://lore.kernel.org/all/20220317081305.739554-1-mkl@pengutronix.de
Cc: stable@vger.kernel.org
Reported-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: ems_usb: ems_usb_start_xmit(): fix double dev_kfree_skb() in error path</title>
<updated>2022-04-08T11:57:19+00:00</updated>
<author>
<name>Hangyu Hua</name>
<email>hbh25y@gmail.com</email>
</author>
<published>2022-02-28T08:36:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3f71f499395545119383f10760b8b19703d2a7dd'/>
<id>3f71f499395545119383f10760b8b19703d2a7dd</id>
<content type='text'>
commit c70222752228a62135cee3409dccefd494a24646 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
beacause can_put_echo_skb() deletes the original skb and
can_free_echo_skb() deletes the cloned skb.

Link: https://lore.kernel.org/all/20220228083639.38183-1-hbh25y@gmail.com
Fixes: 702171adeed3 ("ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface")
Cc: stable@vger.kernel.org
Cc: Sebastian Haas &lt;haas@ems-wuensche.com&gt;
Signed-off-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c70222752228a62135cee3409dccefd494a24646 upstream.

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
beacause can_put_echo_skb() deletes the original skb and
can_free_echo_skb() deletes the cloned skb.

Link: https://lore.kernel.org/all/20220228083639.38183-1-hbh25y@gmail.com
Fixes: 702171adeed3 ("ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface")
Cc: stable@vger.kernel.org
Cc: Sebastian Haas &lt;haas@ems-wuensche.com&gt;
Signed-off-by: Hangyu Hua &lt;hbh25y@gmail.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: rcar_canfd: rcar_canfd_channel_probe(): register the CAN device when fully ready</title>
<updated>2022-02-25T16:46:54+00:00</updated>
<author>
<name>Lad Prabhakar</name>
<email>prabhakar.mahadev-lad.rj@bp.renesas.com</email>
</author>
<published>2022-02-21T22:59:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c5048a7b2c23ab589f3476a783bd586b663eda5b'/>
<id>c5048a7b2c23ab589f3476a783bd586b663eda5b</id>
<content type='text'>
Register the CAN device only when all the necessary initialization is
completed. This patch makes sure all the data structures and locks are
initialized before registering the CAN device.

Link: https://lore.kernel.org/all/20220221225935.12300-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Reported-by: Pavel Machek &lt;pavel@denx.de&gt;
Signed-off-by: Lad Prabhakar &lt;prabhakar.mahadev-lad.rj@bp.renesas.com&gt;
Reviewed-by: Pavel Machek &lt;pavel@denx.de&gt;
Reviewed-by: Ulrich Hecht &lt;uli+renesas@fpond.eu&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Register the CAN device only when all the necessary initialization is
completed. This patch makes sure all the data structures and locks are
initialized before registering the CAN device.

Link: https://lore.kernel.org/all/20220221225935.12300-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Reported-by: Pavel Machek &lt;pavel@denx.de&gt;
Signed-off-by: Lad Prabhakar &lt;prabhakar.mahadev-lad.rj@bp.renesas.com&gt;
Reviewed-by: Pavel Machek &lt;pavel@denx.de&gt;
Reviewed-by: Ulrich Hecht &lt;uli+renesas@fpond.eu&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: gs_usb: change active_channels's type from atomic_t to u8</title>
<updated>2022-02-25T08:14:34+00:00</updated>
<author>
<name>Vincent Mailhol</name>
<email>mailhol.vincent@wanadoo.fr</email>
</author>
<published>2022-02-14T23:48:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=035b0fcf02707d3c9c2890dc1484b11aa5335eb1'/>
<id>035b0fcf02707d3c9c2890dc1484b11aa5335eb1</id>
<content type='text'>
The driver uses an atomic_t variable: gs_usb:active_channels to keep
track of the number of opened channels in order to only allocate
memory for the URBs when this count changes from zero to one.

However, the driver does not decrement the counter when an error
occurs in gs_can_open(). This issue is fixed by changing the type from
atomic_t to u8 and by simplifying the logic accordingly.

It is safe to use an u8 here because the network stack big kernel lock
(a.k.a. rtnl_mutex) is being hold. For details, please refer to [1].

[1] https://lore.kernel.org/linux-can/CAMZ6Rq+sHpiw34ijPsmp7vbUpDtJwvVtdV7CvRZJsLixjAFfrg@mail.gmail.com/T/#t

Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")
Link: https://lore.kernel.org/all/20220214234814.1321599-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol &lt;mailhol.vincent@wanadoo.fr&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The driver uses an atomic_t variable: gs_usb:active_channels to keep
track of the number of opened channels in order to only allocate
memory for the URBs when this count changes from zero to one.

However, the driver does not decrement the counter when an error
occurs in gs_can_open(). This issue is fixed by changing the type from
atomic_t to u8 and by simplifying the logic accordingly.

It is safe to use an u8 here because the network stack big kernel lock
(a.k.a. rtnl_mutex) is being hold. For details, please refer to [1].

[1] https://lore.kernel.org/linux-can/CAMZ6Rq+sHpiw34ijPsmp7vbUpDtJwvVtdV7CvRZJsLixjAFfrg@mail.gmail.com/T/#t

Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")
Link: https://lore.kernel.org/all/20220214234814.1321599-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol &lt;mailhol.vincent@wanadoo.fr&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
</pre>
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</entry>
<entry>
<title>can: etas_es58x: change opened_channel_cnt's type from atomic_t to u8</title>
<updated>2022-02-25T08:14:34+00:00</updated>
<author>
<name>Vincent Mailhol</name>
<email>mailhol.vincent@wanadoo.fr</email>
</author>
<published>2022-02-12T11:27:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f4896248e9025ff744b4147e6758274a1cb8cbae'/>
<id>f4896248e9025ff744b4147e6758274a1cb8cbae</id>
<content type='text'>
The driver uses an atomic_t variable: struct
es58x_device::opened_channel_cnt to keep track of the number of opened
channels in order to only allocate memory for the URBs when this count
changes from zero to one.

While the intent was to prevent race conditions, the choice of an
atomic_t turns out to be a bad idea for several reasons:

- implementation is incorrect and fails to decrement
  opened_channel_cnt when the URB allocation fails as reported in
  [1].

- even if opened_channel_cnt were to be correctly decremented,
  atomic_t is insufficient to cover edge cases: there can be a race
  condition in which 1/ a first process fails to allocate URBs
  memory 2/ a second process enters es58x_open() before the first
  process does its cleanup and decrements opened_channed_cnt. In
  which case, the second process would successfully return despite
  the URBs memory not being allocated.

- actually, any kind of locking mechanism was useless here because
  it is redundant with the network stack big kernel lock
  (a.k.a. rtnl_lock) which is being hold by all the callers of
  net_device_ops:ndo_open() and net_device_ops:ndo_close(). c.f. the
  ASSERST_RTNL() calls in __dev_open() [2] and __dev_close_many()
  [3].

The atmomic_t is thus replaced by a simple u8 type and the logic to
increment and decrement es58x_device:opened_channel_cnt is simplified
accordingly fixing the bug reported in [1]. We do not check again for
ASSERST_RTNL() as this is already done by the callers.

[1] https://lore.kernel.org/linux-can/20220201140351.GA2548@kili/T/#u
[2] https://elixir.bootlin.com/linux/v5.16/source/net/core/dev.c#L1463
[3] https://elixir.bootlin.com/linux/v5.16/source/net/core/dev.c#L1541

Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
Link: https://lore.kernel.org/all/20220212112713.577957-1-mailhol.vincent@wanadoo.fr
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Vincent Mailhol &lt;mailhol.vincent@wanadoo.fr&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The driver uses an atomic_t variable: struct
es58x_device::opened_channel_cnt to keep track of the number of opened
channels in order to only allocate memory for the URBs when this count
changes from zero to one.

While the intent was to prevent race conditions, the choice of an
atomic_t turns out to be a bad idea for several reasons:

- implementation is incorrect and fails to decrement
  opened_channel_cnt when the URB allocation fails as reported in
  [1].

- even if opened_channel_cnt were to be correctly decremented,
  atomic_t is insufficient to cover edge cases: there can be a race
  condition in which 1/ a first process fails to allocate URBs
  memory 2/ a second process enters es58x_open() before the first
  process does its cleanup and decrements opened_channed_cnt. In
  which case, the second process would successfully return despite
  the URBs memory not being allocated.

- actually, any kind of locking mechanism was useless here because
  it is redundant with the network stack big kernel lock
  (a.k.a. rtnl_lock) which is being hold by all the callers of
  net_device_ops:ndo_open() and net_device_ops:ndo_close(). c.f. the
  ASSERST_RTNL() calls in __dev_open() [2] and __dev_close_many()
  [3].

The atmomic_t is thus replaced by a simple u8 type and the logic to
increment and decrement es58x_device:opened_channel_cnt is simplified
accordingly fixing the bug reported in [1]. We do not check again for
ASSERST_RTNL() as this is already done by the callers.

[1] https://lore.kernel.org/linux-can/20220201140351.GA2548@kili/T/#u
[2] https://elixir.bootlin.com/linux/v5.16/source/net/core/dev.c#L1463
[3] https://elixir.bootlin.com/linux/v5.16/source/net/core/dev.c#L1541

Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
Link: https://lore.kernel.org/all/20220212112713.577957-1-mailhol.vincent@wanadoo.fr
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Vincent Mailhol &lt;mailhol.vincent@wanadoo.fr&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
</pre>
</div>
</content>
</entry>
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