Hello All, I wanted to know what is the best way to generate the kernel crash dump on kernel panic, after doing some searching, i came to know we can use kexec to load a new kernel on the kernel, i followed the instruction from the following links http://www.dedoimedo.com/computers/kdump.html http://www.developertutorials.com/tutorials/linux/reboot-linux-faster-072204... I do found that the kernel load properly with the, kexec -l option followed by kexec -e option, but when i set the kernel to be loaded on kernel panic using the option kexec -p, i see that after kernel crash, the system just hangs, it wont even try to load the new kernel. following are the commands am using. Can some one point, if there is any thing wrong with this. chkconfig kdump on /etc/init.d/kdump start kexec -l --append="`cat /proc/cmdline`" --initrd=/boot/initrd.img-2.6.35.10-kdump /boot/vmlinuz-2.6.35.10-kdump kexec -e works fine and loads the kernel successfully, i will be able to see *starting new kernel* in the shell * * * chkconfig kdump on /etc/init.d/kdump start * kexec -p --append="`cat /proc/cmdline`" --initrd=/boot/initrd.img-2.6.35.10* -kdump ** /boot/vmlinuz-2.6.35.10 -kdump * * * i simulate the panic by using echo 1 > /proc/sys/kernel/sysrq echo c > /proc/sysrq-trigger which just crash the kernel and system hangs, and it does not show any message *starting new kernel.* * * Thanks,
kernel. following are the commands am using. Can some one point, if there is any thing wrong with this. chkconfig kdump on /etc/init.d/kdump start kexec -l --append="`cat /proc/cmdline`" --initrd=/boot/initrd.img-2.6.35.10-kdump /boot/vmlinuz-2.6.35.10-kdump kexec -e works fine and loads the kernel successfully, i will be able to see starting new kernel in the shell chkconfig kdump on /etc/init.d/kdump start kexec -p --append="`cat /proc/cmdline`" --initrd=/boot/initrd.img-2.6.35.10 -kdump /boot/vmlinuz-2.6.35.10 -kdump i simulate the panic by using echo 1 > /proc/sys/kernel/sysrq echo c > /proc/sysrq-trigger which just crash the kernel and system hangs, and it does not show any message starting new kernel. does /var/crash or kdump target directory as mentioned in /etc/kdump.conf exists? sometime it may be a while before it starts to dump if memory on machine is huge and you have set kdump level to dump everything.
thx,thayumanavar s.
Hi, does /var/crash or kdump target directory as mentioned in
/etc/kdump.conf exists?
One thing i forgot to mention is in my root there is not configuration file /etc/sysconfig/kdump or /etc/kdump.conf, is this anything to do with this and not even /var/crash, i got the latest kexec-tool source from the git and build it.
sometime it may be a while before it starts to dump if memory on machine is huge and
i almost left my system for an hour, but it was in the same hang state.
you have set kdump level to dump everything.
Where else can be the configuration file other then /etc/sysconfig/kdump or /etc/kdump.conf.
does /var/crash or kdump target directory as mentioned in /etc/kdump.conf exists?
One thing i forgot to mention is in my root there is not configuration file /etc/sysconfig/kdump or /etc/kdump.conf, is this anything to do with this and not even /var/crash, i got the latest kexec-tool source from the git and build it. This file will be provided the kexec-tools rpm of any distribution. I am not sure whether the git repo has it or not. It would be easier (say if you are on redhat, you can yum install kexec-tools, yum install kernel-kdump, boot it in kdump kernel) if your distribution rpms to set it up. You need to append crashkernel=128M@16M on kernel command line and boot it into the kdump kernel ( that you might have built with certain kexec related options enabled). Also you create directory /var/crash if it does not exist and you need to regenerate or create a new initrd for the second kernel( that will boot when crash happens). thx,thayumanavar s.
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swathi suresh -
Thayumanavar S