OMAP: DSS2: Documentation for DSS2

[safe/jmp/linux-2.6] / Documentation / oops-tracing.txt

diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt
index c563842..b152e81 100644 (file)
--- a/Documentation/oops-tracing.txt
+++ b/Documentation/oops-tracing.txt
@@ -30,17 +30,20 @@ the disk is not available then you have three options :-
 
 (1) Hand copy the text from the screen and type it in after the machine
     has restarted.  Messy but it is the only option if you have not
 
 (1) Hand copy the text from the screen and type it in after the machine
     has restarted.  Messy but it is the only option if you have not

-    planned for a crash.
+    planned for a crash. Alternatively, you can take a picture of
+    the screen with a digital camera - not nice, but better than
+    nothing.  If the messages scroll off the top of the console, you
+    may find that booting with a higher resolution (eg, vga=791)
+    will allow you to read more of the text. (Caveat: This needs vesafb,
+    so won't help for 'early' oopses)

 
 (2) Boot with a serial console (see Documentation/serial-console.txt),
     run a null modem to a second machine and capture the output there
     using your favourite communication program.  Minicom works well.
 
 
 (2) Boot with a serial console (see Documentation/serial-console.txt),
     run a null modem to a second machine and capture the output there
     using your favourite communication program.  Minicom works well.
 

-(3) Patch the kernel with one of the crash dump patches.  These save
-    data to a floppy disk or video rom or a swap partition.  None of
-    these are standard kernel patches so you have to find and apply
-    them yourself.  Search kernel archives for kmsgdump, lkcd and
-    oops+smram.
+(3) Use Kdump (see Documentation/kdump/kdump.txt),
+    extract the kernel ring buffer from old memory with using dmesg
+    gdbmacro in Documentation/kdump/gdbmacros.txt.

 
 
 Full Information
 
 
 Full Information


@@ -83,6 +86,20 @@ stuff are the values reported by the Oops - you can just cut-and-paste
 and do a replace of spaces to "\x" - that's what I do, as I'm too lazy 
 to write a program to automate this all).
 
 and do a replace of spaces to "\x" - that's what I do, as I'm too lazy 
 to write a program to automate this all).
 

+Alternatively, you can use the shell script in scripts/decodecode.
+Its usage is:  decodecode < oops.txt
+
+The hex bytes that follow "Code:" may (in some architectures) have a series
+of bytes that precede the current instruction pointer as well as bytes at and
+following the current instruction pointer.  In some cases, one instruction
+byte or word is surrounded by <> or (), as in "<86>" or "(f00d)".  These
+<> or () markings indicate the current instruction pointer.  Example from
+i386, split into multiple lines for readability:
+
+Code: f9 0f 8d f9 00 00 00 8d 42 0c e8 dd 26 11 c7 a1 60 ea 2b f9 8b 50 08 a1
+64 ea 2b f9 8d 34 82 8b 1e 85 db 74 6d 8b 15 60 ea 2b f9 <8b> 43 04 39 42 54
+7e 04 40 89 42 54 8b 43 04 3b 05 00 f6 52 c0
+

 Finally, if you want to see where the code comes from, you can do
 
        cd /usr/src/linux
 Finally, if you want to see where the code comes from, you can do
 
        cd /usr/src/linux


@@ -231,6 +248,15 @@ characters, each representing a particular tainted value.
   6: 'B' if a page-release function has found a bad page reference or
      some unexpected page flags.
 
   6: 'B' if a page-release function has found a bad page reference or
      some unexpected page flags.
 

+  7: 'U' if a user or user application specifically requested that the
+     Tainted flag be set, ' ' otherwise.
+
+  8: 'D' if the kernel has died recently, i.e. there was an OOPS or BUG.
+
+  9: 'A' if the ACPI table has been overridden.
+
+ 10: 'W' if a warning has previously been issued by the kernel.
+

 The primary reason for the 'Tainted: ' string is to tell kernel
 debuggers if this is a clean kernel or if anything unusual has
 occurred.  Tainting is permanent: even if an offending module is
 The primary reason for the 'Tainted: ' string is to tell kernel
 debuggers if this is a clean kernel or if anything unusual has
 occurred.  Tainting is permanent: even if an offending module is