Questions tagged [kdump]

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Unable to Get Kernel Crash Dump on Kernel Panic

I'm using kexec-tools to get a crash dump of kernel on kernel panic. However, when I trigger the panic using sysrq-trigger, the system freezes. I have to power off and then power on to restore the ...
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13 views

Analyzing vmcore using crash to find process causing crash - the offending process is different with every crash

My centos 7 server kept crashing so I tried installing crash and kexec to get memory dumps. I've got several now and when I try analyzing the vmcore dumps with crash, it's usually one of the two ...
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9 views

Is there a way to make kdump dump its log onto the frame buffer?

I was wondering if there is a way to make kdump dump its log onto the frame buffer (the screen where the xserver is displayed) rather than into the system console. I know this isn't really possible ...
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0answers
2k views

kdump.service failed to start on CentOS 8

Issue kdump.service fails to start on CentOS 8 virtual machine on Google Cloud. Restarting the service keeps reproducing the same error. It seems the secure boot is causing the issue or is at least ...
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0answers
145 views

Is UN state and D state in Linux processes are same?

I want to understand is the UN and D process state is the same? During the analysis of vmcore (crash dump) I have found lots of UN state processes. And when I googled it I hardly found any document ...
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1answer
1k views

How to reset the video mode of the Intel driver i915 for the kexec-ed kernel so I can see what kexec kernel is doing?

I'm running Arch Linux and I've set up kdump so that when the current kernel panics(or I manually induce a crash via sysrq+c) then another kernel(the kexec kernel) starts up in order to create a crash ...
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0answers
239 views

Why is crash command exiting without prompt?

I've installed a debug kernel and enabled kdump. The coredump was generated successfully, but when I try to load the vmcore after reboot, crash command just quit without prompt: # crash /usr/lib/...
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0answers
419 views

Not able to save crash dump using kdump

I have a VPS server on amazon's AWS Lightsail service. I've been testing kdump using the following two commands(to trigger an automatic kernel crash): # echo 1 > /proc/sys/kernel/sysrq # echo c &...
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0answers
147 views

Kernel crashes at different points

I have made a custom board using Tegra TK1 ARM processor. I have compiled uboot and kernel for it and flashed into it. Now when it starts booting, sometimes it boots successfully while sometimes ...
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0answers
1k views

Hard lockup triggers reboot but no panic and no kdump

I have been trying to debug random system freezes when running the 4.14.93-rt kernel. To this end, I have enabled the lockup detector in the kernel using the following config: ...
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1answer
236 views

Why there are two entries for crashkernel parameter in the grub.conf file?

I'm trying to enable kdump on a server but in the grub configuration file, there are two entries for the crashkernel parameter for each OS entry. I know that this parameter is used to allocate memory ...
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3answers
1k views

kdump in CentOS 7

I wanted to migrate to CentOS 7.5 from CentOS 6.9. during installation I saw an option kdump that i could enable or disable. I wonder what is kdump and disabling it has any bad effect on server? I ...
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1answer
154 views

kernel.core_pattern has no effect on vmcore file name

On my RHEL7.4 VM, in /etc/kdump.conf I have set the path /var/myorg/myhost. In /etc/sysctl.conf kernel.core_pattern = core.%e.%p.%h.%t. The generated vmcore name is not as mentioned in core_pattern ...
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1answer
1k views

kdump: kexec_file_load failed: Cannot assign requested address

Issue: SERVER:~ # systemctl start kdump.service Job for kdump.service failed because the control process exited with error code. See "systemctl status kdump.service" and "journalctl -xe" for details....
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1answer
5k views

echo c > /proc/sysrq-trigger doesn't reboot the system

I am trying to collect a core dump in result of kernel panic. Installed and configured kdump, but when executing echo c > /proc/sysrq-trigger, everything just hangs and the reboot doesn't happen. I ...
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0answers
282 views

Crashkernel not starting after crash

I am trying to start a crash kernel using Linux's Kernel Crash Dump. Both of the host and crash kernel are compiled linux-4.13.16 kernel. Unfortunately, the crash kernel fails to start after the crash ...
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670 views

Cannot get kernel crash dump saved and reboot

I need to get a crash dump of my linux kernel. I am going to describe the scenario: Hardware: Notebook Dell E5450. Linux Distribution: Linux Mint 18.3 (Ubuntu 16.04). SysRq: enabled by /etc/sysctl.d/...
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1answer
137 views

Could the capture kernel be used as a normal kernel after a kexec?

I have read about the kexec/kdump facilities, we know that crashed/panic'ed kernel is made available via /proc/vmcore. I have heard people use kexec based booting to bypass EFI/BIOS/FW initialization ...
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1answer
551 views

I have a kdump kernel core dump; how can I analyze it?

After installing kdump-related packages and yet another hang, I now have a: /var/crash/kexec_cmd file. But what can I do with it? Should I use the command-line crash utility? I tried to, but it ...