Public bug reported: To debug kernel crashes, I have installed and configured the kernel crash dumps on a 14.04 system (with Wily HWE Stack, but the problem exist with older an newer kernels too).
I have used the following documentation: https://wiki.ubuntu.com/Kernel/CrashdumpRecipe https://help.ubuntu.com/lts/serverguide/kernel-crash-dump.html The default kernel option is: crashkernel=384M-:128M The output of kdump-config show: # kdump-config show USE_KDUMP: 1 KDUMP_SYSCTL: kernel.panic_on_oops=1 KDUMP_COREDIR: /var/crash crashkernel addr: 0x24000000 current state: ready to kdump kexec command: /sbin/kexec -p --command-line="BOOT_IMAGE=/vmlinuz-4.2.0-30-generic root=/dev/mapper/VolGroup00-rootlv ro quiet splash vt.handoff=7 irqpoll maxcpus=1 nousb" --initrd=/boot/initrd.img-4.2.0-30-generic /boot/vmlinuz-4.2.0-30-generic When using the "echo c > /proc/sysrq-trigger" to induce a crash, nothing happens after the Oops gets printed on the console. I have to manually turn the system off an on again, and of course, no crash dump is found in /var/crash. After raising the reserved memory to 256MB (crashkernel=384M-:256M), and triggering the crash using the sysrq, the new kernel gets started shortly after the Oops, and after the following reboot the crash dump is in /var/crash, as expected. The system is a Lenovo T450s with amd64 installation. ** Affects: kexec-tools (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to kexec-tools in Ubuntu. https://bugs.launchpad.net/bugs/1555103 Title: kdump: does not generate a dump on 14.04, because the reserved memory is too low Status in kexec-tools package in Ubuntu: New Bug description: To debug kernel crashes, I have installed and configured the kernel crash dumps on a 14.04 system (with Wily HWE Stack, but the problem exist with older an newer kernels too). I have used the following documentation: https://wiki.ubuntu.com/Kernel/CrashdumpRecipe https://help.ubuntu.com/lts/serverguide/kernel-crash-dump.html The default kernel option is: crashkernel=384M-:128M The output of kdump-config show: # kdump-config show USE_KDUMP: 1 KDUMP_SYSCTL: kernel.panic_on_oops=1 KDUMP_COREDIR: /var/crash crashkernel addr: 0x24000000 current state: ready to kdump kexec command: /sbin/kexec -p --command-line="BOOT_IMAGE=/vmlinuz-4.2.0-30-generic root=/dev/mapper/VolGroup00-rootlv ro quiet splash vt.handoff=7 irqpoll maxcpus=1 nousb" --initrd=/boot/initrd.img-4.2.0-30-generic /boot/vmlinuz-4.2.0-30-generic When using the "echo c > /proc/sysrq-trigger" to induce a crash, nothing happens after the Oops gets printed on the console. I have to manually turn the system off an on again, and of course, no crash dump is found in /var/crash. After raising the reserved memory to 256MB (crashkernel=384M-:256M), and triggering the crash using the sysrq, the new kernel gets started shortly after the Oops, and after the following reboot the crash dump is in /var/crash, as expected. The system is a Lenovo T450s with amd64 installation. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kexec-tools/+bug/1555103/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
