Re: Kexec (and HyperV) (was: Re: Dimdows Decay Syndrome Continues)

On 8 Feb 2025 08:44:20 GMT, vallor wrote:

On Sat, 8 Feb 2025 06:36:16 -0000 (UTC), Lawrence D'Oliveiro
<ldo@nz.invalid> wrote in <vo6u10$3ue2q$1@dont-email.me>:
 

Doesn’t RHEL support kexec, which
allows the old Linux kernel to pass control to the new one without
actually disrupting the userland?

 
You're thinking of live kernel patching.  kexec_load(2) load a kernel
that you can have execute if the current kernel crashes.  You do this
for debugging, usually.

Bit more than that <https://manpages.debian.org/kexec_load(2)>:

    The kexec_load() system call loads a new kernel that can be
    executed later by reboot(2).

And one of the functions of the latter
<https://manpages.debian.org/reboot(2)> is:

    LINUX_REBOOT_CMD_KEXEC
      (RB_KEXEC, 0x45584543, since Linux 2.6.13). Execute a kernel
      that has been loaded earlier with kexec_load(2).