I recently installed Fedora 38 on a Sager laptop with Intel processor and Nvidia RTX GPU. After upgrading, kernel 6.4.4 showed up in GRUB. When I select it, all I get on the screen is a single underscore. The screen is frozen that way until my computer goes to sleep. If I wake it up after an hour or so, then it’s on the login page.
How do I debug this? I’ve tried a number of suggestions from articles to get log text to show up during boot, but nothing has worked.
Once the user is able to log in, the first thing I would do is run dmesg > dmesg.boot then peruse that file. If there is a long hang as indicated the times in the first column would show where that hang occurred.
journalctl -b > journal.boot would provide more information but the times there are daytimes and not time-since-power-on as is shown in dmesg so one would need to correlate the times to match up the entries.
One could also use something like systemd-analyze plot > boot.svg to obtain a graphical plot of the boot progress . That fiie could then be opened with a browser or similar to view timings during the boot.
There is very nice option to dmesg to show your the times in wall clock time: dmesg --reltime
[Jul23 22:25] perf: interrupt took too long (2507 > 2500), lowering kernel.perf_event_max_sample_rate to 79000
[Jul24 19:06] perf: interrupt took too long (3134 > 3133), lowering kernel.perf_event_max_sample_rate to 63000
[Jul27 12:13] systemd-journald: Data hash table of /var/log/journal/23861aed63d748da85011d84ee28e601/system.journal has a fill level at 75.0 (170043 of 226723 items, 67108864 file size, 394 bytes per hash table item), suggesting rotation.
[ +0.000881] systemd-journald: /var/log/journal/23861aed63d748da85011d84ee28e601/system.journal: Journal header limits reached or header out-of-date, rotating.
I have this alias in my .bashrc as I always want wall-clock timestamps
I didn’t say linux falls apart. I was suggesting that it didn’t load because the system has been on for a long time so the image is probably enormous. I opened it in Inkscape and it’s like 100,000 pixels across, so I’m going to try again after reboot.
You should be able to kill the process without rebooting. There are many linux tools that will show you when a process is using excessive resources (CPU time, RAM). You should try to provide enough detail to allow others to reproduce a problem.