From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/Documentation/init.txt | 49 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 kernel/Documentation/init.txt (limited to 'kernel/Documentation/init.txt') diff --git a/kernel/Documentation/init.txt b/kernel/Documentation/init.txt new file mode 100644 index 000000000..535ad5e82 --- /dev/null +++ b/kernel/Documentation/init.txt @@ -0,0 +1,49 @@ +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: +0) Set "debug" kernel parameter (in bootloader config file or CONFIG_CMDLINE) + to get more detailed kernel messages. +A) 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 |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 -- cgit 1.2.3-korg