** Description changed: + [Impact] + + Currently it's not possible to use the kdump functionality in xenial + when running the linux-azure kernel. The problem is actually caused but + several factors: + + 1. kexec fails to parse /proc/kcore and thus fails to load the crash + kernel. That's similar to bug #1713940 and it's related to 4.10+ + kernels. + + 2. When the crash kernel boots, a bug in KASLR causes it to crash in a + very early stage. For the user, it seems the system just rebooted after + the crash. + + 3. Currently in azure, crashkernel=128G is not enough to boot and run + the dump procedure with 4.11+ kernels. That value needs to be increased + in order to kdump to succeed. + + 4. After the vmcore is dumped, the current version of crash in xenial is + not able to parse it. All the necessary fixes are already upstream and + can be backported. + + [Test Case] + + 1. Install the linux-azure kernel in an azure instance (although it's + possible to run linux-azure in bare metal or kvm, the KASLR issue only + is triggered in azure). + + 2. Follow the instructions in https://help.ubuntu.com/lts/serverguide + /kernel-crash-dump.html to setup kdump and manually trigger a crash + using /proc/sysrq-trigger. + + The vmcore must be generated and it should be possible to inspect it + using crash. + + [Regression Potential] + + Since both kexec-tools and crash are being changed to support 4.10+ + kernels, it's very important that they continue to handle 4.4 kernels + properly. + + The same steps above can be used to test linux-generic for regressions. + + [Other Info] + + Original description: + + --8<-- Because the linux-azure kernel is based on 4.11, kexec on 16.04 gives the following error: kdump-tools[1436]: ELF core (kcore) parse failed Perhaps the artful kexec-tools should be backported? + --8<--
-- 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/1712867 Title: [Hyper-V] 16.04 kexec-tools doesn't match linux-azure Status in crash package in Ubuntu: In Progress Status in kexec-tools package in Ubuntu: In Progress Status in linux-azure package in Ubuntu: In Progress Status in kexec-tools source package in Xenial: In Progress Status in linux-azure source package in Xenial: In Progress Bug description: [Impact] Currently it's not possible to use the kdump functionality in xenial when running the linux-azure kernel. The problem is actually caused but several factors: 1. kexec fails to parse /proc/kcore and thus fails to load the crash kernel. That's similar to bug #1713940 and it's related to 4.10+ kernels. 2. When the crash kernel boots, a bug in KASLR causes it to crash in a very early stage. For the user, it seems the system just rebooted after the crash. 3. Currently in azure, crashkernel=128G is not enough to boot and run the dump procedure with 4.11+ kernels. That value needs to be increased in order to kdump to succeed. 4. After the vmcore is dumped, the current version of crash in xenial is not able to parse it. All the necessary fixes are already upstream and can be backported. [Test Case] 1. Install the linux-azure kernel in an azure instance (although it's possible to run linux-azure in bare metal or kvm, the KASLR issue only is triggered in azure). 2. Follow the instructions in https://help.ubuntu.com/lts/serverguide /kernel-crash-dump.html to setup kdump and manually trigger a crash using /proc/sysrq-trigger. The vmcore must be generated and it should be possible to inspect it using crash. [Regression Potential] Since both kexec-tools and crash are being changed to support 4.10+ kernels, it's very important that they continue to handle 4.4 kernels properly. The same steps above can be used to test linux-generic for regressions. [Other Info] Original description: --8<-- Because the linux-azure kernel is based on 4.11, kexec on 16.04 gives the following error: kdump-tools[1436]: ELF core (kcore) parse failed Perhaps the artful kexec-tools should be backported? --8<-- To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/crash/+bug/1712867/+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
