All devices behind a SPI controller have the same udev ID_PATH property.
This is a problem for predicable network names for CAN controllers.
CAN controllers, in contrast to Ethernet controllers, don't have a MAC
Address, so there's no way to tell two CAN controllers on the same SPI
host controller apart:
$ udevadm info /sys/class/net/can0
P: /devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.1/net/can0
L: 0
E: DEVPATH=/devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.1/net/can0
E: INTERFACE=can0
E: IFINDEX=3
E: SUBSYSTEM=net
E: USEC_INITIALIZED=11187199
E: ID_PATH=platform-fe204000.spi
E: ID_PATH_TAG=platform-fe204000_spi
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/can0
E: TAGS=:systemd:
$ udevadm info /sys/class/net/can1
P: /devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.0/net/can1
L: 0
E: DEVPATH=/devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.0/net/can1
E: INTERFACE=can1
E: IFINDEX=4
E: SUBSYSTEM=net
E: USEC_INITIALIZED=11192211
E: ID_PATH=platform-fe204000.spi
E: ID_PATH_TAG=platform-fe204000_spi
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/can1
E: TAGS=:systemd:
With this the chip select number is added to the ID_PATH, to make
predictable network names possible.
$ sudo udevadm info /sys/class/net/can0
P: /devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.1/net/can0
L: 0
E: DEVPATH=/devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.1/net/can0
E: INTERFACE=can0
E: IFINDEX=3
E: SUBSYSTEM=net
E: USEC_INITIALIZED=11187199
E: ID_PATH=platform-fe204000.spi-cs-1
E: ID_PATH_TAG=platform-fe204000_spi-cs-1
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/can0
E: TAGS=:systemd:
$ sudo udevadm info /sys/class/net/can1
P: /devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.0/net/can1
L: 0
E: DEVPATH=/devices/platform/soc/fe204000.spi/spi_master/spi0/spi0.0/net/can1
E: INTERFACE=can1
E: IFINDEX=4
E: SUBSYSTEM=net
E: USEC_INITIALIZED=11192211
E: ID_PATH=platform-fe204000.spi-cs-0
E: ID_PATH_TAG=platform-fe204000_spi-cs-0
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/can1
E: TAGS=:systemd:
When the system is under heavy load, it can happen that the unit cache
is refreshed for an unrelated reason (in the test I simulate this by
attempting to start a non-existing unit). The new unit is found and
accounted for in the cache, but it's ignored since we are loading
something else.
When we actually look for it, by attempting to start it, the cache is
up to date so no refresh happens, and starting fails although we have
it loaded in the cache.
When the unit state is set to UNIT_NOT_FOUND, mark the timestamp in
u->fragment_loadtime. Then when attempting to load again we can check
both if the cache itself needs a refresh, OR if it was refreshed AFTER
the last failed attempt that resulted in the state being
UNIT_NOT_FOUND.
Update the test so that this issue reproduces more often.
Since the hwdb update from a79be2f807
the systemd-hwdb-update service started timing out under ASan when
compiled with gcc, as we started tripping over the 3 minutes timeout.
This affects only gcc runs, since the current gcc on Arch still suffers
from the detect_stack_use_after_return performance penalty[0]. Until
the fixed gcc is present in the respective repositories, let's bump
the timeout to 4 minutes, as we might not be able to upgrade right
away, due to systemd/systemd#16199.
Before the hwdb update:
[ 7958.292540] systemd[63]: systemd-hwdb-update.service: Executing: /usr/bin/time systemd-hwdb update
[ 7958.304005] systemd[1]: systemd-journald.service: Got notification message from PID 44 (FDSTORE=1)
[ 7958.314434] systemd[1]: systemd-journald.service: Added fd 3 (n/a) to fd store.
[ 8008.520082] systemd[1]: systemd-journald.service: Got notification message from PID 44 (WATCHDOG=1)
[ 8068.520151] systemd[1]: systemd-journald.service: Got notification message from PID 44 (WATCHDOG=1)
[ 8125.682843] time[63]: 84.47user 82.92system 2:47.50elapsed 99%CPU (0avgtext+0avgdata 811512maxresident)k
[ 8125.682843] time[63]: 0inputs+19680outputs (0major+25000853minor)pagefaults 0swaps
After the hwdb update:
[ 6215.491958] systemd[63]: systemd-hwdb-update.service: Executing: /usr/bin/time systemd-hwdb update
[ 6215.503380] systemd[1]: systemd-journald.service: Got notification message from PID 44 (FDSTORE=1)
[ 6215.514172] systemd[1]: systemd-journald.service: Added fd 3 (n/a) to fd store.
[ 6329.392918] systemd[1]: systemd-journald.service: Got notification message from PID 44 (WATCHDOG=1)
[ 6394.920205] time[63]: 89.48user 89.98system 2:59.55elapsed 99%CPU (0avgtext+0avgdata 812764maxresident)k
[ 6394.920205] time[63]: 0inputs+20568outputs (0major+27318354minor)pagefaults 0swaps
[0] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94910
