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Topic: xorg fails to start, logs show a seg fault, no unwind info found (Read 1591 times) previous topic - next topic
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xorg fails to start, logs show a seg fault, no unwind info found

Hi all.

Well... thank goodness I recently got riverwm working on wayland (albeit with some stuttering issues that are related to the NVIDIA 545 drivers.

Today when I attempted to start my usual X server with bspwm, the xorg server wouldn't start, complaining. I believe it to be a race condition as I simply attempted again and it worked. But then after doing some work and restarting my computer, it consistently won't log into my X session. Following the error's instructions, I checked the logs in ~/.local/share/xorg and found this at the most recent log:

Code: [Select]
[    27.731] (--) NVIDIA(GPU-0): 
[    27.843] (EE) 
[    27.843] (EE) Backtrace:
[    27.844] (EE) 0: /usr/lib/Xorg (xorg_backtrace+0x2ed) [0x58ba0178b88d]
[    27.844] (EE) 1: /usr/lib/libc.so.6 (__sigaction+0x50) [0x74c2bef61710]
[    27.846] (EE) 2: /usr/lib/libnvidia-glcore.so.545.29.06 (_nv023glcore+0x1beab) [0x74c2bcb4abcb]
[    27.846] (EE) unw_get_proc_name failed: no unwind info found [-10]
[    27.846] (EE) 3: /usr/lib/nvidia/xorg/libglxserver_nvidia.so (?+0x0) [0x74c2b8d38404]
[    27.846] (EE) 
[    27.846] (EE) Segmentation fault at address 0x1e1
[    27.846] (EE) 
Fatal server error:
[    27.846] (EE) Caught signal 11 (Segmentation fault). Server aborting
[    27.846] (EE) 
[    27.847] (EE)

This appears to be a recent error, but I am unsure which recent update could have broken this. My paclogs don't show any specific updates to NVIDIA. A couple days ago the mesa and vulkan packages did have an update, and I did find some old arch forum posts that complained about mesa breaking xorg, but this was a couple years ago.

Anyways, any insights into this issue would be highly appreciated. My setup on wayland is still far from complete, and I still rely on Xorg for quite a bit.

Thanks as always in advance.

EDIT: This is definitely a race condition. I just opened up a TTY and startx worked...

EDIT: Yeah, further attempts at starting x11 via startx appears to start session every 10 or so tries. I'm very much at a loss here.

Re: xorg fails to start, logs show a seg fault, no unwind info found

Reply #1 –
Ok, I solved it, but am looking into best practices when setting up wayland.

It appears that in my following of different config options when setting up wayland (via Arch Wiki Docs and others) for getting the nvidia proprietary drivers working. I accidentally put configuration options for nvidia use into two places that caused this condition.

To give some context, earlier this month I wanted to get riverwm on wayland working as I wanted to prepare for an eventual migration to wayland. Following the Arch Wiki docs I eventually documented my solution as thus:

Under /etc/modprobe.d directory, I made a file called nvidia_drm.conf and put this config options in it:

Code: [Select]
options nvidia_drm modeset=1 fbdev=1

And also these config flags  under the MODULES=() line in /etc/mkinitcpio.conf:

Code: [Select]
nvidia nvidia_modeset nvidia_uvm nvidia_drm

And this config option in the GRUB_CMDLINE_LINUX_DEFAULT line of /etc/default grub:

Code: [Select]
nvidia-drm.modeset=1

And running mkinitcpio -P as well as grub-mkconfig -o /boot/grub/grub.cfg

Everything worked fine on both x11 and wayland for the last month, but my guess is either I was lucky and never ran into the aforementioned issue until today, OR an update to mesa possibly broke this configuration.

In my attempts to troubleshoot the issue, I ran mkinitcpio -P to no effect. Thinking on the fact that the configuration options in my new /etc/modprobe.d/nvidia_drm.conf file were somewhat repetitive, as they echoed the config flag passed to /etc/default/grub file. I removed the /etc/modprobe.d/nvidia_drm.conf, reran mkinitcpio -P, and all appears to now be working as expected.

That said, I did like having the output in my TTY be the approrpriate font size, as it recognized my nvidia card earlier in the boot process.

Have I made some sort of mistake here? Is there any way I can have my cake and eat it too? (meaning can I have nice output in my tty that the nvidia_drm.conf file gave me while still having Xorg not encounter this race condition?).

Thanks again in advance for any possible input to my issue here!

Re: xorg fails to start, logs show a seg fault, no unwind info found

Reply #2 –
UPDATE:

So it seems the race condition is still occurring. I'm noticing a change in my screen resolution when loading udevd during the boot process shortly after GRUB runs. I notice if I reboot, the resolution is closer to my actual screen resolution. I must have messed something up when setting up wayland and nvidia. I've posted my configurations thus far and again, am at a bit of a loss as to which configuration option is throwing off xorg here, but it has to be the /etc/mkinitcpio.conf or the /etc/default grub configuration files. I'll be working and updating this later just as a log of my process.