kernel/linux.git/drivers/net/can/slcan, branch v6.2

can: slcan: fix freed work crash

2022-12-07T09:32:24+00:00

The LTP test pty03 is causing a crash in slcan: BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 348 Comm: kworker/0:3 Not tainted 6.0.8-1-default #1 openSUSE Tumbleweed 9d20364b934f5aab0a9bdf84e8f45cfdfae39dab Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014 Workqueue: 0x0 (events) RIP: 0010:process_one_work (/home/rich/kernel/linux/kernel/workqueue.c:706 /home/rich/kernel/linux/kernel/workqueue.c:2185) Code: 49 89 ff 41 56 41 55 41 54 55 53 48 89 f3 48 83 ec 10 48 8b 06 48 8b 6f 48 49 89 c4 45 30 e4 a8 04 b8 00 00 00 00 4c 0f 44 e0 <49> 8b 44 24 08 44 8b a8 00 01 00 00 41 83 e5 20 f6 45 10 04 75 0e RSP: 0018:ffffaf7b40f47e98 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff9d644e1b8b48 RCX: ffff9d649e439968 RDX: 00000000ffff8455 RSI: ffff9d644e1b8b48 RDI: ffff9d64764aa6c0 RBP: ffff9d649e4335c0 R08: 0000000000000c00 R09: ffff9d64764aa734 R10: 0000000000000007 R11: 0000000000000001 R12: 0000000000000000 R13: ffff9d649e4335e8 R14: ffff9d64490da780 R15: ffff9d64764aa6c0 FS: 0000000000000000(0000) GS:ffff9d649e400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000036424000 CR4: 00000000000006f0 Call Trace: worker_thread (/home/rich/kernel/linux/kernel/workqueue.c:2436) kthread (/home/rich/kernel/linux/kernel/kthread.c:376) ret_from_fork (/home/rich/kernel/linux/arch/x86/entry/entry_64.S:312) Apparently, the slcan's tx_work is freed while being scheduled. While slcan_netdev_close() (netdev side) calls flush_work(&sl->tx_work), slcan_close() (tty side) does not. So when the netdev is never set UP, but the tty is stuffed with bytes and forced to wakeup write, the work is scheduled, but never flushed. So add an additional flush_work() to slcan_close() to be sure the work is flushed under all circumstances. The Fixes commit below moved flush_work() from slcan_close() to slcan_netdev_close(). What was the rationale behind it? Maybe we can drop the one in slcan_netdev_close()? I see the same pattern in can327. So it perhaps needs the very same fix. Fixes: cfcb4465e992 ("can: slcan: remove legacy infrastructure") Link: https://bugzilla.suse.com/show_bug.cgi?id=1205597 Reported-by: Richard Palethorpe Tested-by: Petr Vorel Cc: Dario Binacchi Cc: Wolfgang Grandegger Cc: Marc Kleine-Budde Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: linux-can@vger.kernel.org Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org Cc: Max Staudt Signed-off-by: Jiri Slaby (SUSE) Reviewed-by: Max Staudt Link: https://lore.kernel.org/all/20221201073426.17328-1-jirislaby@kernel.org Signed-off-by: Marc Kleine-Budde

can: dev: fix skb drop check

2022-11-07T13:00:27+00:00

In commit a6d190f8c767 ("can: skb: drop tx skb if in listen only mode") the priv->ctrlmode element is read even on virtual CAN interfaces that do not create the struct can_priv at startup. This out-of-bounds read may lead to CAN frame drops for virtual CAN interfaces like vcan and vxcan. This patch mainly reverts the original commit and adds a new helper for CAN interface drivers that provide the required information in struct can_priv. Fixes: a6d190f8c767 ("can: skb: drop tx skb if in listen only mode") Reported-by: Dariusz Stojaczyk Cc: Vincent Mailhol Cc: Max Staudt Signed-off-by: Oliver Hartkopp Acked-by: Vincent Mailhol Link: https://lore.kernel.org/all/20221102095431.36831-1-socketcan@hartkopp.net Cc: stable@vger.kernel.org # 6.0.x [mkl: patch pch_can, too] Signed-off-by: Marc Kleine-Budde

can: tree-wide: advertise software timestamping capabilities

2022-07-28T09:44:01+00:00

Currently, some CAN drivers support hardware timestamping, some do not. But userland has no method to query which features are supported (aside maybe of getting RX messages and observe whether or not hardware timestamps stay at zero). The canonical way for a network driver to advertised what kind of timestamping it supports is to implement ethtool_ops::get_ts_info(). This patch only targets the CAN drivers which *do not* support hardware timestamping. For each of those CAN drivers, implement the get_ts_info() using the generic ethtool_op_get_ts_info(). This way, userland can do: | $ ethtool --show-time-stamping canX to confirm the device timestamping capacities. N.B. the drivers which support hardware timestamping will be migrated in separate patches. Signed-off-by: Vincent Mailhol Link: https://lore.kernel.org/all/20220727101641.198847-6-mailhol.vincent@wanadoo.fr [mkl: mscan: add missing mscan_ethtool_ops] Signed-off-by: Marc Kleine-Budde

can: slcan: add software tx timestamps

2022-07-28T07:30:36+00:00

TX timestamps were added to the can_put_echo_skb() function of can_dev modules in [1]. However, slcan does not rely on that function and as such does not offer TX timestamping. Add a call to skb_tx_timestamp() in the slc_xmit() function so that the module now supports TX software timestamps. [1] commit 741b91f1b0ea ("can: dev: can_put_echo_skb(): add software tx timestamps") Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=741b91f1b0ea34f00f6a7d4539b767c409291fcf CC: Dario Binacchi Signed-off-by: Vincent Mailhol Link: https://lore.kernel.org/all/20220727101641.198847-4-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde

MAINTAINERS: Add maintainer for the slcan driver

2022-07-28T07:14:42+00:00

At the suggestion of its author Oliver Hartkopp ([1]), I take over the maintainer-ship and add myself to the authors of the driver. [1] https://lore.kernel.org/all/507b5973-d673-4755-3b64-b41cb9a13b6f@hartkopp.net Suggested-by: Oliver Hartkopp Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/all/20220728070254.267974-8-dario.binacchi@amarulasolutions.com Signed-off-by: Marc Kleine-Budde

can: slcan: add support for listen-only mode

2022-07-28T07:14:42+00:00

For non-legacy, i.e. ip based configuration, add support for listen-only mode. If listen-only is requested send a listen-only ("L\r") command instead of an open ("O\r") command to the adapter. Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/all/20220728070254.267974-7-dario.binacchi@amarulasolutions.com Signed-off-by: Marc Kleine-Budde

can: slcan: use the generic can_change_mtu()

2022-07-28T07:14:42+00:00

It is useless to define a custom function that does nothing but always return the same error code. Better to use the generic can_change_mtu() function. Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/all/20220728070254.267974-6-dario.binacchi@amarulasolutions.com Signed-off-by: Marc Kleine-Budde

can: slcan: change every `slc' occurrence in `slcan'

2022-07-28T07:14:35+00:00

In the driver there are parts of code where the prefix `slc' is used and others where the prefix `slcan' is used instead. The patch replaces every occurrence of `slc' with `slcan', except for the netdev functions where, to avoid compilation conflicts, it was necessary to replace `slc' with `slcan_netdev'. The patch does not make any functional changes. Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/all/20220728070254.267974-5-dario.binacchi@amarulasolutions.com Signed-off-by: Marc Kleine-Budde

can: slcan: remove legacy infrastructure

2022-07-28T07:13:11+00:00

Taking inspiration from the drivers/net/can/can327.c driver and at the suggestion of its author Max Staudt, I removed legacy stuff like `SLCAN_MAGIC' and `slcan_devs' resulting in simplification of the code and its maintainability. The use of slcan_devs is derived from a very old kernel, since slip.c is about 30 years old, so today's kernel allows us to remove it. The .hangup() ldisc function, which only called the ldisc .close(), has been removed since the ldisc layer calls .close() in a good place anyway. The old slcanX name has been dropped in order to use the standard canX interface naming. The ioctl SIOCGIFNAME can be used to query the name of the created interface. Furthermore, there are several ways to get stable interfaces names in user space, e.g. udev or systemd-networkd. The `maxdev' module parameter has also been removed. CC: Max Staudt Signed-off-by: Dario Binacchi Reviewed-by: Max Staudt Link: https://lore.kernel.org/all/20220728070254.267974-4-dario.binacchi@amarulasolutions.com Signed-off-by: Marc Kleine-Budde

can: slcan: remove useless header inclusions

2022-07-28T07:10:47+00:00

Include only the necessary headers. Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/all/20220728070254.267974-3-dario.binacchi@amarulasolutions.com Signed-off-by: Marc Kleine-Budde