Messages in this thread | | | Date | Mon, 1 Feb 2010 23:10:51 -0800 (PST) | From | David Rientjes <> | Subject | Re: [PATCH] Improve usability in case of init binary failure |
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On Sun, 27 Dec 2009, Andreas Mohr wrote:
> Well, took quite a while longer, partly due to broken Broadcom USB host > (OpenWrt fix to be submitted) and non-working USB-audio on nicer platforms. > > Took most of the comments into account (thanks!), improved some wording. > > Patch against current git, compile- and runtime-tested, > checkpatch.pl'd (with a single nice hierarchy warning resulting from mixing > git diff output and manual /dev/null diffing). > > Thanks! >
It looks like this patch got mangled when added to mmotm-2010-02-01-16-25 in init-mainc-improve-usability-in-case-of-init-binary-failure.patch since it added init.txt to the root directory instead of Documentation, even though the patch below is correct.
> Signed-off-by: Andreas Mohr <andi@lisas.de> > > diff --git a/init/main.c b/init/main.c > index dac44a9..33748c6 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -836,7 +836,8 @@ static noinline int init_post(void) > run_init_process("/bin/init"); > run_init_process("/bin/sh"); > > - panic("No init found. Try passing init= option to kernel."); > + panic("No init found. Try passing init= option to kernel. " > + "See Linux Documentation/init.txt for guidance."); > } > > static int __init kernel_init(void * unused) > --- /dev/null 2009-12-27 16:25:29.521258205 +0100 > +++ Documentation/init.txt 2009-12-27 15:47:46.000000000 +0100 > @@ -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 <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>
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