how can i log all the messages during boot ?

exponential · 07-24-2006, 09:15 PM

i configured and compiled 2.6.17 (on slackware 10.2 with 2.4.31 - the kernel that comes with this distribution) but when i boot my new image, it crushes: kernel panic(0). the thing is i would want to try and do some debugging. the /var/log/syslog doesn't contain information about booting the new kernel, just for the old one, although i boot my new one with the "debug" option

any kind of help would be appreciated

drkstr · 07-25-2006, 01:12 AM

/var/log/dmesg usually contains all the stuff that gets dumped to the screen during boot. syslog gets loaded later on so it will not contain any info if your kernel crashes. I think it's called by either the rc.S or the rc.M, either way, this is much later in the boot process.

regards,
...drkstr

Alien Bob · 07-25-2006, 04:41 AM

You could try configuring /etc/lilo.conf and /etc/inittab to start a serial console, and then use a second PC and nullmodem cable to display the boot process in a serial terminal such as minicom. That way, if the kernel crashes, you can copy/paste the serial terminal's log or get a screendump.

Eric

Berhanie · 07-25-2006, 07:21 AM

Quote:

/var/log/dmesg usually contains all the stuff that gets dumped to the screen during boot.

Unfortunately, this is also done at the rc.M stage.

exponential · 07-25-2006, 01:49 PM

thank you guys
i think i'll try and redirect the output, as bob said.

for anyone else who might need this, it can be done with an argument passed to the kernel at the boot time, "console=/dev/something" (i hope i'm not wrong with this)
for more info man bootparam