mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 21:51:40 +00:00
9d85025b04
Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters on an user's manual book. As we'll be numbering the user's manual, remove the manual numbering from SecurityBugs. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
53 lines
2.6 KiB
ReStructuredText
53 lines
2.6 KiB
ReStructuredText
Explaining the dreaded "No init found." boot hang message
|
|
=========================================================
|
|
|
|
OK, so you've got this pretty unintuitive message (currently located
|
|
in init/main.c) and are wondering what the H*** went wrong.
|
|
Some high-level reasons for failure (listed roughly in order of execution)
|
|
to load the init binary are:
|
|
|
|
A) Unable to mount root FS
|
|
B) init binary doesn't exist on rootfs
|
|
C) broken console device
|
|
D) binary exists but dependencies not available
|
|
E) binary cannot be loaded
|
|
|
|
Detailed explanations:
|
|
|
|
A) Set "debug" kernel parameter (in bootloader config file or CONFIG_CMDLINE)
|
|
to get more detailed kernel messages.
|
|
B) make sure you have the correct root FS type
|
|
(and ``root=`` kernel parameter points to the correct partition),
|
|
required drivers such as storage hardware (such as SCSI or USB!)
|
|
and filesystem (ext3, jffs2 etc.) are builtin (alternatively as modules,
|
|
to be pre-loaded by an initrd)
|
|
C) Possibly a conflict in ``console= setup`` --> initial console unavailable.
|
|
E.g. some serial consoles are unreliable due to serial IRQ issues (e.g.
|
|
missing interrupt-based configuration).
|
|
Try using a different ``console= device`` or e.g. ``netconsole=``.
|
|
D) e.g. required library dependencies of the init binary such as
|
|
``/lib/ld-linux.so.2`` missing or broken. Use
|
|
``readelf -d <INIT>|grep NEEDED`` to find out which libraries are required.
|
|
E) make sure the binary's architecture matches your hardware.
|
|
E.g. i386 vs. x86_64 mismatch, or trying to load x86 on ARM hardware.
|
|
In case you tried loading a non-binary file here (shell script?),
|
|
you should make sure that the script specifies an interpreter in its shebang
|
|
header line (``#!/...``) that is fully working (including its library
|
|
dependencies). And before tackling scripts, better first test a simple
|
|
non-script binary such as ``/bin/sh`` and confirm its successful execution.
|
|
To find out more, add code ``to init/main.c`` to display kernel_execve()s
|
|
return values.
|
|
|
|
Please extend this explanation whenever you find new failure causes
|
|
(after all loading the init binary is a CRITICAL and hard transition step
|
|
which needs to be made as painless as possible), then submit patch to LKML.
|
|
Further TODOs:
|
|
|
|
- Implement the various ``run_init_process()`` invocations via a struct array
|
|
which can then store the ``kernel_execve()`` result value and on failure
|
|
log it all by iterating over **all** results (very important usability fix).
|
|
- try to make the implementation itself more helpful in general,
|
|
e.g. by providing additional error messages at affected places.
|
|
|
|
Andreas Mohr <andi at lisas period de>
|