VirtualBox Hangs Pre-Init Due To Ext2FS Fault

[James Clarke]

Hi,
I have been suffering a lot from my Hurd system (running in VirtualBox) hanging 
at startup, just after "Hurd server bootstrap..." but before "INIT: version 
2.88 booting".

I have been able to trace it back to getblk.c:248 (unsigned long addr_per_block 
= EXT2_ADDR_PER_BLOCK (sblock);) in ext2_getblk. It faults because sblock is 
NULL.

I have traced the execution with debugging statements, and what seems to happen 
is as follows:

1. diskfs_remount is called (because root is remounted as rw)
2. RPCs are inhibited
3. diskfs_reload_global_state is called
4. sblock is set to NULL
5. While this is happening, ext2_getblk is called

If you’re lucky, the superblock is read and sblock is set to point to this data 
before 5 (or at least before it gets to dereferencing sblock). If not, sblock 
is still NULL and thus a page fault is raised, causing the system to be stuck.

Does anyone have an idea how this situation could be occurring?

James Clarke