linux-3.8.1 required config missing in LFS 7.3 Stable book

[Zach]

I've built a stock LFS-7.3 system (build completed 7/12/13) and seem to have found a missing kernel config requirement in the LFS (stable) book page (​http://www.linuxfromscratch.org/lfs/view/stable/chapter08/kernel.html) for linux-3.8.1. The page states the following:

---

Due to recent changes in udev, be sure to select:

Device Drivers --->

Generic Driver Options --->

Maintain a devtmpfs filesystem to mount at /dev

---

While this is not a udev issue (and thus should not be in the same note), I would like to propose that the following be added to the Linux kernel section of the book due to a problem encountered without this configuration:

---

File Systems --->

Pseudo Filesystems --->

Tmpfs virtual memory file system support (former shm fs)

---

Without this configuration, I encountered the issue described here: ​http://www.mail-archive.com/lfs-support@linuxfromscratch.org/msg20137.html.

An excerpt from the post describing the issue exactly as it occurred for me:

---

What my issue is is when booting I see that Init is running then like a line mabe 2 down I start getting errors. I believe my first issue with the other errors are all mabe tied into the fact I'm getting a:

"mount: wrong fstype,bad option, bad superblock on tmpfs, missing codepage or helper program, or other error"

then directly below this I start getting:

"mkdir: cannot create directory '/run/var': Read-only file system"

this is followed with the same error but for lock and shm.

after this I get an error every line or most of them atleast about /run/var/bootlog file or directory not found errors.

---

Later in the post, another user correctly (both for me and the OP) identified the issue:

---

Do you have tmpfs support enabled in your kernel? It's found under File Systems > Pseudo File Systems.

---

Setting the option and recompiling the kernel resolved the issue perfectly. After looking over the hints on the page, it looks like this required config doesn't seem to be addressed, and the "make mrproper" at the beginning of the kernel config leaves this item disabled by default, causing a repeatable breakage in the book process.

I don't know if this will affect future versions, or if this is even the right place to submit this, but I thought it might be of interest to the LFS Book team.

I've been a fan of LFS since 6.2. Keep up the good work guys. :)

[bdubbs@…]

make defconfig sets CONFIG_TMPFS by default. I suppose we could mention that command as a good starting place for creating the kernel configuration.

[Zach]

Sounds like a good idea. In the meantime it might be a good idea to toss it into the errata for the book. I imagine it's not a horribly common issue, but it might make it easier for people building LFS, especially when they are compiling without a previous kernel config to work from.

[bdubbs@…]

Added a comment to the note on the kernel page about 'make defconfig'.

Fixed at revision 10306.