Unix and Linux Stack Exchange
Unix and Linux Stack Exchange

Questions tagged [kexec]

kexec is a system call that enables to load and boot into another kernel from the currently running kernel.

kexec is a system call that enables to load and boot into another kernel from the currently running kernel.

http://linux.die.net/man/8/kexec

29 questions
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Reboot without having to decrypt LUKS partitions?

Is there a way to kexec reboot a running kernel without having to decrypt an encrypted LUKS root filesystem? I'd imagine not, but I'm not sure if there's a workaround for this.
Naftuli Kay
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How to check if currently running Linux kernel has been loaded with kexec?

By checking I mean something quite rock-solid, i. e., trying to analyse loader's configuration or available kernel files and matching to uname's output clearly isn't an option.
poige
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5 answers

Kexec to GRUB (or to Syslinux, or Windows)

I have an application where I need to boot to Linux, execute automated scripts and then automatically boot to Windows. Can I use Kexec to run grub? Another use case would be to boot a Linux kernel to update the processor microcode, and then kexec to…
rudib
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kexec and USE_GRUB_CONFIG

I find kexec very useful to speed-up the reboot of Linux servers. One parameter into /etc/default/kexec is USE_GRUB_CONFIG. This parameter is meant to "read Grub configuration file". But I don't understand what governs the choice between setting it…
Gregory MOUSSAT
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4
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1 answer

kexec reboot no longer skips firmware/hard reboot after upgrade to ubuntu 20.04

(Posting here rather than the Ubuntu subsite because I don't think it's specifically related to Ubuntu...) I've previously been successfully using kexec-reboot -lr from the exceptionally useful page here. After an upgrade from 18.04 to 20.04,…
ljwobker
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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…
tomptz
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kexec doesn't unmount root filesystem

With a Debian Jessie 8.0, freshly installed (with systemd), I installed kexec. When I restart the computer with the reboot command, this invoke kexec. The reboot is ok but I have a message into the logs: systemd-fsck[xxx]: /dev/sda1 file system not…
Gregory MOUSSAT
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does the second kernel need kexec enabled

It's clear that you need the kexec syscalls in the 'first' kernel. But does the kernel that should get loaded (with kexec_load and reboot) need to be compiled with kexec? If yes, what extra code needs to get executed inside the kernel to do a kexec…
Uroc327
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2 answers

Easy way initrd to chain loading another kernel with kexec

I have here a machine which won't boot 64-bit kernels (it has efi32 with a little bit of... uncommon firmware). Currently, my only way to boot my 64-bit linux system is: Booting a 32-bit distro from a boot/live cd, Using kexec to boot my own 64 bit…
peterh
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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 dump so that I can later inspect it. The problem…
user353741
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kexec: relocate_kernel fails

I am not able to get kexec to work. For x86_64 relocate_kernel fails to store information for jumping back. Kexec stops in movq %r9, CP_PA_TABLE_PAGE(%r11). works fine for kernel 4.4.162, doesn't work for 4.19.2 also works with 4.19.16 How can I…
Jewgeni T.
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Boot rescue kernel at high memory address using kexec on arm

Summary: Crashkernel boots at 512MB address in RAM with kexec -e/-l but not with kexec -p - why? Embedded platform with Marvell Armada XP (MV78460) (ARMv7 with 4 cores) and 1GB of RAM. production kernel: customized Linux 3.4.91 rescue kernel:…
Hans W. Heckel
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kexec crashing when booting a kernel without initramfs (ARM)

First, a few details about the setup: Linux-3.14.1 ARM am335x chip U-Boot bootloader What I am trying to achieve: U-Boot loads a kernel that contains an initramfs (call this kernel 1). U-Boot executes this kernel. Kernel 1 loads kernel 2, which…
Phil Williams
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How should I fix a failed kexec that produces "CPUs are stuck in the kernel" in dmesg?

I have built both a kernel from the Raspberry Pi sources and kexec-tools for arm64, and booted my kernel on a Raspberry Pi 4. When I attempt to run kexec, it produces no output, exits with a nonzero return code, and an error message is posted to…
Micah R Ledbetter
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Kexec into new kernel, but I can't access the initramfs prompt!

I used kexec to successfully load my kernel, but it's just printing dmesg lines. How do I get out of this to drop into the initramfs prompt? Ctrl-Alt-F2 just loads a black screen and ctrl-c does nothing. Here is my kexec commandline: kexec -l…
SurpriseDog
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