Add gdb macro which print the kernel ring buffer into kdump docs
Signed-off-by: Akinobu Mita <[email protected]>
--- 2.6/Documentation/kdump/gdbmacros.txt.orig 2006-01-06 10:47:06.000000000 +0900
+++ 2.6/Documentation/kdump/gdbmacros.txt 2006-01-06 10:47:46.000000000 +0900
@@ -177,3 +177,25 @@ document trapinfo
'trapinfo <pid>' will tell you by which trap & possibly
addresthe kernel paniced.
end
+
+
+define dmesg
+ set $i = 0
+ set $end_idx = (log_end - 1) & (log_buf_len - 1)
+
+ while ($i < logged_chars)
+ set $idx = (log_end - 1 - logged_chars + $i) & (log_buf_len - 1)
+
+ if ($idx + 100 <= $end_idx) || \
+ ($end_idx <= $idx && $idx + 100 < log_buf_len)
+ printf "%.100s", &log_buf[$idx]
+ set $i = $i + 100
+ else
+ printf "%c", log_buf[$idx]
+ set $i = $i + 1
+ end
+ end
+end
+document dmesg
+ print the kernel ring buffer
+end
Kdump has been merged and supported on several architectures.
It is better to encourage to use kdump rather than non standard
kernel crash dump patches.
Signed-off-by: Akinobu Mita <[email protected]>
--- 2.6/Documentation/oops-tracing.txt.orig 2006-01-06 10:55:53.000000000 +0900
+++ 2.6/Documentation/oops-tracing.txt 2006-01-06 10:58:30.000000000 +0900
@@ -41,11 +41,9 @@ the disk is not available then you have
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.
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