[bootlin/training-materials updates] master: debugging: slides: add more information on kdump (22becc09)
Clément Léger
clement.leger at bootlin.com
Wed Nov 16 18:48:51 CET 2022
Repository : https://github.com/bootlin/training-materials
On branch : master
Link : https://github.com/bootlin/training-materials/commit/22becc09494c761a01aa206ee1029e94ca394e31
>---------------------------------------------------------------
commit 22becc09494c761a01aa206ee1029e94ca394e31
Author: Clément Léger <clement.leger at bootlin.com>
Date: Wed Nov 16 18:48:51 2022 +0100
debugging: slides: add more information on kdump
Signed-off-by: Clément Léger <clement.leger at bootlin.com>
>---------------------------------------------------------------
22becc09494c761a01aa206ee1029e94ca394e31
.../debugging-kernel-debugging.tex | 40 ++++++++++++++++------
1 file changed, 29 insertions(+), 11 deletions(-)
diff --git a/slides/debugging-kernel-debugging/debugging-kernel-debugging.tex b/slides/debugging-kernel-debugging/debugging-kernel-debugging.tex
index 5d0fe385..793b01a7 100644
--- a/slides/debugging-kernel-debugging/debugging-kernel-debugging.tex
+++ b/slides/debugging-kernel-debugging/debugging-kernel-debugging.tex
@@ -131,29 +131,48 @@
\end{itemize}
\end{frame}
-\begin{frame}
- \frametitle{kexec \& kdump}
+\begin{frame}[fragile]
+ \frametitle{kexec \& kdump (1/2)}
\begin{itemize}
- \item On panic, kdump will start a "dump-capture kernel" directly from the
+ \item On panic, kdump will start a "kdump kernel" directly from the
kernel that crashed
\begin{itemize}
- \item Most of the time, a specific minimal dump-capture kernel is compiled
+ \item Most of the time, a specific minimal kdump kernel is compiled
for that task
\end{itemize}
- \item This kernel will allow to dump the \code{/proc/vmcore} file from
- {\em procfs}
- \item {\em kexec} works by saving some RAM for the crash kernel execution at
+ \item {\em kexec} works by saving some RAM for the kdump kernel execution at
startup
\begin{itemize}
\item \code{crashkernel} parameter should be set to specify the crash
kernel dedicated physical memory region
\item \code{crashkernel=size[KMG][@offset[KMG]]}
\end{itemize}
- \item {\em kexec-tools} are then used to prepare a kernel to be executed in
- this memory zone.
+ \item {\em kexec-tools} are then used to prepare a kdump kernel to be
+ executed in this memory zone using the \code{kexec} command
+ \end{itemize}
+ \begin{block}{}
+ \begin{minted}[fontsize=\footnotesize]{console}
+$ kexec --type zImage --dtb=my_dtb.dtb --initrd=myinitrd --append="ttyS0
+ max_cpus=1 reset_devices" -p myzImage
+ \end{minted}
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{kexec \& kdump (2/2)}
+ \begin{itemize}
+ \item The command line additional options depends on the architecture
+ \item See \kdochtml{admin-guide/kdump/kdump} for more comprehensive
+ explanations on how to setup the kdump kernel with \code{kexec}.
+ \item Finally, on panic, the kernel will reboot into the kdump kernel
+ allowing the user to dump \code{/dev/vmcore} onto whatever media
\item Additional user-space services and tools allows to automatically
collect and dump the vmcore file to remote location.
- \item \kdochtml{admin-guide/kdump/kdump}
+ \begin{itemize}
+ \item See kdump systemd service and the \code{makedumpfile} tool which
+ can also compress the vmcore file into a smaller file.
+ \item \url{https://github.com/makedumpfile/makedumpfile}
+ \end{itemize}
\end{itemize}
\end{frame}
@@ -180,7 +199,6 @@
\end{itemize}
\end{frame}
-
\begin{frame}[fragile]
\frametitle{{\em crash} example}
\begin{itemize}
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