On Thu, Oct 16, 2025 at 10:26 AM Warner Losh <[email protected]> wrote:

>
>
> On Thu, Oct 16, 2025 at 8:12 AM Alan Somers <[email protected]> wrote:
>
>> The "boot" command will give you a vague description like "shutdown" or
>> "crash".
>>
>
> boot command? I don't have this on my system. How do yo uget that?
>

Sorry, I meant "last".


>
>
>> If a crash was the cause then maybe your system isn't configured to make
>> core dumps.  I suggest forcing a crash with "sysctl debug.kdb.panic=1"
>> while you watch the screen to see what happens.
>>
>
> Yea. If it is a reboot, and crash dumps are enabled, and there's nothing
> is in /var/log/messages, you have limited options.
>
> If there's a BMC, and it speaks IPMI, there might be something in the IPMI
> log if it was hardware triggered (ipmitool sel list):
>    1 |  Pre-Init  |0000001024| Processor #0xe4 | Presence detected |
> Asserted
>    2 |  Pre-Init  |0000000000| System Event | OEM System boot event |
> Asserted
>    3 |  Pre-Init  |0000000001| System Event | Timestamp Clock Sync |
> Asserted
>    4 | 04/17/23 | 16:07:49 MDT | System Event | Timestamp Clock Sync |
> Asserted
>    5 | 04/17/23 | 16:11:12 MDT | OS Boot #0x22 | boot completed - device
> not specified | Asserted
>    6 | 04/17/23 | 16:20:42 MDT | System Event | OEM System boot event |
> Asserted
>    7 | 04/17/23 | 16:23:16 MDT | System Event | OEM System boot event |
> Asserted
>    8 | 04/17/23 | 16:28:44 MDT | System Event | OEM System boot event |
> Asserted
>    9 | 04/17/23 | 16:30:25 MDT | OS Boot #0x22 | boot completed - device
> not specified | Asserted
> ...
> (oh my, I need to clear my log)
>
> Warner
>
>> On Thu, Oct 16, 2025 at 7:35 AM void <[email protected]> wrote:
>>
>>> Hi,
>>>
>>> I'm trying to work out why a reboot is happening.
>>> line power is fine. PSU is fine.
>>> There's no coredump.
>>> Nothing in /var/log/messages console.log all.log or daemon.log
>>>
>>> Is there a thing I can set somewhere which when enabled will
>>> capture why a system reboots?
>>>
>>> thnx
>>> --
>>>
>>>

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