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Source at commit fbf123cd4cc0c097fe9a99c90109ebb2a5e94a50 created 10 years 3 months ago. By Lars-Peter Clausen, dma: jz4740: Dequeue descriptor from active list before completing it | |
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1 | Explaining the dreaded "No init found." boot hang message |
2 | ========================================================= |
3 | |
4 | OK, so you've got this pretty unintuitive message (currently located |
5 | in init/main.c) and are wondering what the H*** went wrong. |
6 | Some high-level reasons for failure (listed roughly in order of execution) |
7 | to load the init binary are: |
8 | A) Unable to mount root FS |
9 | B) init binary doesn't exist on rootfs |
10 | C) broken console device |
11 | D) binary exists but dependencies not available |
12 | E) binary cannot be loaded |
13 | |
14 | Detailed explanations: |
15 | 0) Set "debug" kernel parameter (in bootloader config file or CONFIG_CMDLINE) |
16 | to get more detailed kernel messages. |
17 | A) make sure you have the correct root FS type |
18 | (and root= kernel parameter points to the correct partition), |
19 | required drivers such as storage hardware (such as SCSI or USB!) |
20 | and filesystem (ext3, jffs2 etc.) are builtin (alternatively as modules, |
21 | to be pre-loaded by an initrd) |
22 | C) Possibly a conflict in console= setup --> initial console unavailable. |
23 | E.g. some serial consoles are unreliable due to serial IRQ issues (e.g. |
24 | missing interrupt-based configuration). |
25 | Try using a different console= device or e.g. netconsole= . |
26 | D) e.g. required library dependencies of the init binary such as |
27 | /lib/ld-linux.so.2 missing or broken. Use readelf -d <INIT>|grep NEEDED |
28 | to find out which libraries are required. |
29 | E) make sure the binary's architecture matches your hardware. |
30 | E.g. i386 vs. x86_64 mismatch, or trying to load x86 on ARM hardware. |
31 | In case you tried loading a non-binary file here (shell script?), |
32 | you should make sure that the script specifies an interpreter in its shebang |
33 | header line (#!/...) that is fully working (including its library |
34 | dependencies). And before tackling scripts, better first test a simple |
35 | non-script binary such as /bin/sh and confirm its successful execution. |
36 | To find out more, add code to init/main.c to display kernel_execve()s |
37 | return values. |
38 | |
39 | Please extend this explanation whenever you find new failure causes |
40 | (after all loading the init binary is a CRITICAL and hard transition step |
41 | which needs to be made as painless as possible), then submit patch to LKML. |
42 | Further TODOs: |
43 | - Implement the various run_init_process() invocations via a struct array |
44 | which can then store the kernel_execve() result value and on failure |
45 | log it all by iterating over _all_ results (very important usability fix). |
46 | - try to make the implementation itself more helpful in general, |
47 | e.g. by providing additional error messages at affected places. |
48 | |
49 | Andreas Mohr <andi at lisas period de> |
50 |
Branches:
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javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
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jz-3.5
jz-3.6
jz-3.6-rc2-pwm
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jz47xx-2.6.38
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9