On 20.10.2025 13:34:42, Marc Kleine-Budde wrote:
Since the commit c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode"), the automatic restart delay can only be set for devices that implement the restart handler struct can_priv::do_set_mode. As it makes no sense to configure a automatic restart for devices that doesn't support it.
However, since systemd commit 13ce5d4632e3 ("network/can: properly handle CAN.RestartSec=0") [1], systemd-networkd correctly handles a restart delay of "0" (i.e. the restart is disabled). Which means that a disabled restart is always configured in the kernel.
On systems with both changes active this causes that CAN interfaces that don't implement a restart handler cannot be brought up by systemd-networkd.
Solve this problem by allowing a delay of "0" to be configured, even if the device does not implement a restart handler.
[1] https://github.com/systemd/systemd/commit/13ce5d4632e395521e6205c954493c7fc1...
Cc: stable@vger.kernel.org Cc: Andrei Lalaev andrey.lalaev@gmail.com Reported-by: Marc Kleine-Budde mkl@pengutronix.de Closes: https://lore.kernel.org/all/20251020-certain-arrogant-vole-of-sunshine-14184... Fixes: c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode") Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de
Applied to linux-can.
Marc