Re: [PATCH v5 03/22] reboot: call liveupdate_reboot() before kexec

[Mike Rapoport <rppt@kernel.org>]

On Fri, Nov 07, 2025 at 04:03:01PM -0500, Pasha Tatashin wrote:
> Modify the reboot() syscall handler in kernel/reboot.c to call
> liveupdate_reboot() when processing the LINUX_REBOOT_CMD_KEXEC
> command.
> 
> This ensures that the Live Update Orchestrator is notified just
> before the kernel executes the kexec jump. The liveupdate_reboot()
> function triggers the final freeze event, allowing participating
> FDs perform last-minute check or state saving within the blackout
> window.
> 
> The call is placed immediately before kernel_kexec() to ensure LUO
> finalization happens at the latest possible moment before the kernel
> transition.
> 
> If liveupdate_reboot() returns an error (indicating a failure during
> LUO finalization), the kexec operation is aborted to prevent proceeding
> with an inconsistent state.
> 
> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> ---
>  kernel/reboot.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/kernel/reboot.c b/kernel/reboot.c
> index ec087827c85c..bdeb04a773db 100644
> --- a/kernel/reboot.c
> +++ b/kernel/reboot.c
> @@ -13,6 +13,7 @@
>  #include <linux/kexec.h>
>  #include <linux/kmod.h>
>  #include <linux/kmsg_dump.h>
> +#include <linux/liveupdate.h>
>  #include <linux/reboot.h>
>  #include <linux/suspend.h>
>  #include <linux/syscalls.h>
> @@ -797,6 +798,9 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
>  
>  #ifdef CONFIG_KEXEC_CORE
>  	case LINUX_REBOOT_CMD_KEXEC:
> +		ret = liveupdate_reboot();
> +		if (ret)
> +			break;

As we discussed elsewhere, let's move the call to liveupdate_reboot() to
kernel_kexec().

>  		ret = kernel_kexec();
>  		break;
>  #endif
> -- 
> 2.51.2.1041.gc1ab5b90ca-goog
> 

-- 
Sincerely yours,
Mike.