watchdog: iTCO_wdt: cannot register miscdev on minor=130 (err=-16).

watchdog: iTCO_wdt: cannot register miscdev on minor=130 (err=-16).

[Paul Menzel]

Dear Linux folks,


Linux 5.4.39 reports the watchdog messages below on a Dell PowerEdge 
T630 with 12x E5-2603 v4 @ 1.70GHz.

     DMI: Dell Inc. PowerEdge T630/0NT78X, BIOS 2.5.4 08/17/2017

```
handsomejack:~$ more /proc/version
Linux version 5.4.39.mx64.334 (root@lol.molgen.mpg.de) (gcc version 
7.5.0 (GCC)) #1 SMP Thu May 7 14:27:50 CEST 2020
handsomejack:~$ grep TCO /boot/config-5.4.39.mx64.334
CONFIG_NETCONSOLE=m
CONFIG_NETCONSOLE_DYNAMIC=y
# CONFIG_SP5100_TCO is not set
CONFIG_ITCO_WDT=y
CONFIG_ITCO_VENDOR_SUPPORT=y
CONFIG_NV_TCO=y
# CONFIG_INTEL_SMARTCONNECT is not set
# CONFIG_EXTCON is not set
handsomejack:~$ dmesg --level=err
[   11.618887] watchdog: iTCO_wdt: cannot register miscdev on minor=130 
(err=-16).
[   11.627956] watchdog: iTCO_wdt: a legacy watchdog module is probably 
present.
handsomejack:~$ dmesg | grep -e iTCO -e watchdog
[   11.603138] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
[   11.609888] iTCO_wdt: Found a Wellsburg TCO device (Version=2, 
TCOBASE=0x0460)
[   11.618887] watchdog: iTCO_wdt: cannot register miscdev on minor=130 
(err=-16).
[   11.627956] watchdog: iTCO_wdt: a legacy watchdog module is probably 
present.
[   11.636462] iTCO_wdt: initialized. heartbeat=30 sec (nowayout=0)
[   11.643679] iTCO_vendor_support: vendor-support=0
handsomejack:~$ ls -l /dev/watchdog
crw------- 1 root root 10, 130 May 26 11:40 /dev/watchdog
```

Together the error and success messages are from the same module are 
confusing me a little. How can I find out the legacy watchdog module?


Kind regards,

Paul

Re: watchdog: iTCO_wdt: cannot register miscdev on minor=130 (err=-16).

[Guenter Roeck]

On 5/26/20 4:21 AM, Paul Menzel wrote:
> Dear Linux folks,
> 
> 
> Linux 5.4.39 reports the watchdog messages below on a Dell PowerEdge T630 with 12x E5-2603 v4 @ 1.70GHz.
> 
>     DMI: Dell Inc. PowerEdge T630/0NT78X, BIOS 2.5.4 08/17/2017
> 
> ```
> handsomejack:~$ more /proc/version
> Linux version 5.4.39.mx64.334 (root@lol.molgen.mpg.de) (gcc version 7.5.0 (GCC)) #1 SMP Thu May 7 14:27:50 CEST 2020
> handsomejack:~$ grep TCO /boot/config-5.4.39.mx64.334
> CONFIG_NETCONSOLE=m
> CONFIG_NETCONSOLE_DYNAMIC=y
> # CONFIG_SP5100_TCO is not set
> CONFIG_ITCO_WDT=y
> CONFIG_ITCO_VENDOR_SUPPORT=y
> CONFIG_NV_TCO=y
> # CONFIG_INTEL_SMARTCONNECT is not set
> # CONFIG_EXTCON is not set
> handsomejack:~$ dmesg --level=err
> [   11.618887] watchdog: iTCO_wdt: cannot register miscdev on minor=130 (err=-16).
> [   11.627956] watchdog: iTCO_wdt: a legacy watchdog module is probably present.
> handsomejack:~$ dmesg | grep -e iTCO -e watchdog
> [   11.603138] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
> [   11.609888] iTCO_wdt: Found a Wellsburg TCO device (Version=2, TCOBASE=0x0460)
> [   11.618887] watchdog: iTCO_wdt: cannot register miscdev on minor=130 (err=-16).
> [   11.627956] watchdog: iTCO_wdt: a legacy watchdog module is probably present.
> [   11.636462] iTCO_wdt: initialized. heartbeat=30 sec (nowayout=0)
> [   11.643679] iTCO_vendor_support: vendor-support=0
> handsomejack:~$ ls -l /dev/watchdog
> crw------- 1 root root 10, 130 May 26 11:40 /dev/watchdog
> ```
> 
> Together the error and success messages are from the same module are confusing me a little. How can I find out the legacy watchdog module?
> 

/dev/watchdog is your legacy watchdog. You should also have /dev/watchdogN
(where N is a number, probably '0') which is the iTCO watchdog. The error
message refers to the inability to create /dev/watchdog because it already
exists, not to the inability to install the driver at all.

You might have some other log messages indicating which other watchdog
is installed. Otherwise you might need to use ioctls on /dev/watchdog
to determine its name. 'lsmod' might also be useful.

Guenter

Re: watchdog: iTCO_wdt: cannot register miscdev on minor=130 (err=-16).

[Guenter Roeck]

Hi Paul,

On Tue, May 26, 2020 at 01:54:40PM +0200, Paul Menzel wrote:
[ ... ]

> 
> I wonder if the error message could be made extended.
> 
Question is what to extend it to. Best we could do would be to report that
the driver will still try to install itself. Since the legacy driver doesn't
use the watchdog infrastructure, the watchdog infrastructure knows nothing
about it, and it can only guess the reason why /dev/watchdog is not
available.

Personally I'd rather see the ipmi watchdog driver to be converted to use
the watchdog subsystem, but that is a bit unlikely to happen.

> > made the default.
> 
> > You might have some other log messages indicating which other watchdog
> > is installed. Otherwise you might need to use ioctls on /dev/watchdog
> > to determine its name. 'lsmod' might also be useful.
> 
> Please find the logs and lsmod output attached. It might be created by the
> IPMI driver.
> 
> ```
> handsomejack:~$ dmesg | grep IPMI
> [    9.890808] IPMI message handler: version 39.2
> [    9.900456] ipmi_si: IPMI System Interface driver
> [   10.080438] ipmi_si dmi-ipmi-si.0: IPMI message handler: Found new BMC
> (man_id: 0x0002a2, prod_id: 0x0100, dev_id: 0x20)
> [   10.113076] ipmi_si dmi-ipmi-si.0: IPMI kcs interface initialized
> [   10.121572] IPMI Watchdog: driver initialized

Yes, that is indeed the case. If you don't want it, you could maybe
blacklist it. Unfortunately it looks like it is built into the kernel,
so you would also have to change your kernel configuration to
CONFIG_IPMI_WATCHDOG=m. Alternatively, you could keep it and just use
/dev/watchdog1. Either case, you should make make sure that it works.

Guenter