How to get dmesg before system hang?

[guyuming]

my system hangs now and then, ctrl + alt + f(1-7) to switch tty also unresponsive.

if i press the power button, i can see messages on screen says system shutting down step by step, like everything is OK.

I am trying to check dmesg, but how can i find the dmesg of the session before hang?

I found only /var/log/dmesg, no /var/log/dmesg.0 or /var/log/dmesg.1.

And i am using OpenRC with seatd, no systemd or elogind.

[Banana]

I'm not sure right now and I can think of other resources:

X11 logs: /var/log/ or in ~/.local/share/xorg/

https://wiki.gentoo.org/wiki/OpenRC#Logging

Or any other log file available in /var/log

[wjb]

/var/log/everything/current includes the date-stamped dmesg messages from sessions - logrotate moves to these other files under /var/log/everything at intervals and deletes them eventually.

[NeddySeagoon]

guyuming,

That sounds like an Xorg issue or something graphics related as the system still does the 'right thing' in response to the power button.

Can you ssh in and get dmesg that way?

[freke]

On OpenRC you can, in /etc/conf.d/bootmisc

Code: Select all

/etc/conf.d/bootmisc:# Save the previous dmesg log to dmesg.old
/etc/conf.d/bootmisc:previous_dmesg=yes

To keep the previous dmesg after reboot.

[Hu]

On OpenRC you can, in /etc/conf.d/bootmisc

Code: Select all

/etc/conf.d/bootmisc:# Save the previous dmesg log to dmesg.old
/etc/conf.d/bootmisc:previous_dmesg=yes

To keep the previous dmesg after reboot.

/var/log/dmesg is only written at boot though, and OP's problem seems to occur some time well after boot. Therefore, preserving the dmesg from the previous boot will not save anything relevant to OP's problem.