Automounting luks USB drive on boot

mantonson · n00b Joined: 07 Jan 2013 Posts: 8 Location: Lincoln, NE

I have a machine at a remote location that has a USB hard drive, encrypted with luks. Only the USB drive is encrypted, root is not (I backup sensitive data remotely to this USB drive). root is /dev/sda, USB is /dev/sdb. I had it setup to automount on system boot, and everything was working fine. Then I switched to the 17.0 profile and rebuilt world, and now it will no longer automount.

I'm using dm-crypt at the boot runlevel to open the luks container, here's my /etc/conf.d/dmcrypt file:

eccerr0r · Posted: Sun Jan 14, 2018 12:52 am Post subject:

Did you recompile your kernel and your USB driver(s) are modules now, causing a race condition?
Since your USB drive is not a root disk, is it a problem to run dm-crypt later on, say, at the default runlevel instead of boot?
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

mantonson · n00b Joined: 07 Jan 2013 Posts: 8 Location: Lincoln, NE

I did move up kernels (4.4.6 to 4.9.72) but all I did was make olddefconfig, nothing changed from previous config.

I could move it runlevels, but then it wouldn’t be ready to mount via fstab I believe.

mantonson · n00b Joined: 07 Jan 2013 Posts: 8 Location: Lincoln, NE

I tried a couple promising kernel boot parameters I found here: https://wiki.gentoo.org/wiki/Handbook:AMD64/Blocks/Booting, namely slowusb and scandelay, but since it's a remote machine I have no idea if they actually took affect (/proc/cmdline shows they were executed). Regardless, they didn't fix the problem.

I'm agreeing, it seems like some sort of timing issue, like udev isn't enumerating /dev/sdb until too late in the process. I did note that /var/log/dmesg doesn't show /dev/sdb until almost the last entry.

mantonson · n00b Joined: 07 Jan 2013 Posts: 8 Location: Lincoln, NE

Interesting - tried going back to my 4.4.6 kernel image, and it maps fine. So it does seem to be related to my new kernel. I'll go recopy my 4.4.6 config file, then try make silentoldconfig instead of make olddefconfig, and see if there are any important new options.

mantonson · n00b Joined: 07 Jan 2013 Posts: 8 Location: Lincoln, NE

OK, so it's definitely related to the new kernel I built. But going through the new options using make silentoldconfig, I didn't see anything obvious. At this point I'm assuming it's not an option as much as just a difference in behavior. Any suggestions?